Statistics


Questions

# Description Question
7451
  1. In a poll, respondents were asked whether they had ever been in a car accident. 177 respondents indicated that they had been in a car accident and 107 respondents said that they had not been in a car accident. If one of these respondents is randomly selected, what is the probability of getting someone who has been in a car accident?
  2. The data set represents the income levels of the members of a country club. Find the probability that a randomly selected member earns at least $102,000 

    INCOME (Thousands of dollars)



    108   128     82   138    85   108    88    76   158   208



    79     98   148    85   128   118    88   168    73   118
  3. In a certain class of students, there are 13 boys from Wilmette, 3 girls from Kenilworth, 11 girls from Wilmette, 6 boys from Glencoe, 5 boys from Kenilworth and 6 girls from Glencoe. If the teacher calls upon a student to answer a question, what is the probability that the student will be from Kenilworth?
  4. Find the probability of correctly answering the first 2 questions on a multiple choice test if random guesses are made and each question has 4 possible answers. 
  1. Of 1906 people who came into a blood bank to give blood, 300 people had high blood pressure. Estimate the probability that the next person who comes in to give blood will have high blood pressure.
Solve the following problems, showing your work:
7446
An important application of regression analysis in accounting is in the estimation of cost. By collecting data on volume and cost and using the least squares method to develop an estimated regression equation relating volume and cost, an accountant can estimate the cost associated with a particular manufacturing operation. Consider the following sample of production volumes and total cost data for a manufacturing operation. 


Production Volume Total Cost 



(Units) ($) 



400 4,000 



450 5,000 



550 5,400 



600 5,900 



700 6,400 



750 7,000 
 
a. Use the data to develop an estimated regression equation that could be used to predict the total cost for a given production volume. 
b. What is the variable cost per unit produced?
c. Compute the coefficient of determination.  What percentage of the variation in total cost can be explained by production volume?
d. The company’s production schedule shows 500 units must be produced next month. What is the estimated total cost for this operation?
level 200 question
7444

Chapter 6

 

Question 1

  • If p = 0.03, confidence also = 0.03.


Answer

 

True

False

 

Question 2

  • It is possible to conduct a one-sample t test even when the population standard deviation is not known.


Answer
    • True
    • False


 

Question 3

  • A normal deviate Z test requires that we know the population standard deviation.


Answer


    True

    False

Question 4

  • In a one-sample t test with a sample size of 30, there are 30 degrees of freedom.


Answer

    True

    False

 

Question 5

  • The mean of any sampling distribution of the mean is the population mean.


Answer

    True

    False

 

Question 6

  • A z score tests the location of _________, while a Z test tests the location of ____________.


Answer

.    

.      a.

.      An individual score, a sample mean.

.    

.      b.

.      An individual score, a population mean.

.    

.      c.

.      A sample mean, a population mean.

.    

.      d.

.      A random score, a nonrandom score.

 

Question 7

  • In a one-sample t test, α =0.05 and t (52) = +2.46. How many degrees of freedom are in this study?


Answer
  • 0
  • 5
  • 5
  • 2


Question 8

  • The rejection region typically falls where in the sampling distribution of the mean?


Answer

.    

.      a.

.      In the center.

.    

.      b.

.      In the tails.

.    

.      c.

.      Sometimes in the center and sometime in the tails.

.    

.      d.

.      Close to the population mean.

Question 9

  • What is the mean of any sampling distribution of the mean?


Answer

.    

.      a.

.      0.

.    

.      b.

.      The sample mean.

.    

.      c.

.      The population mean.

.    

.      d.

.      It depends on the value of the raw scores in the distribution.

  

Question 10

  • A research report says that t (63) = 1.99; p = 0.03. From that information, can you reject the null hypothesis with 95% confidence?


Answer

.    

.      a.

.      Yes.

.    

.      b.

.      No.

.    

.      c.

.      It depends on the sample size.

.    

.      d.

.      It depends on the size of the type 1 error.

 

Question 1

  • The primary contributor to the standard error of the difference between the means is the standard error of the means of the two populations.


Answer

True

False


Question 2

  • Assume a research report says t(43) = 2.37, α <0.02. For this study, confidence is <0.02.


Answer

True

False

 

Question 3

  • If a single set of subjects serves in both treatment groups, the study should be analyzed with an independent subjects t


Answer

True

False

Question 4

  • The region of rejection is in the tails of the distribution.


Answer

True

False


 

Question 5

  • If tabled t is 2.23 and calculated t is 2.24, the calculated t can be considered statistically significant.


Answer

True

False


Question 6

  • In a two-sample t test, α =0.05 and t(74) = +2.15. How many subjects are in this study?


Answer

.   72.

.   73.

.   74.

.   76.

.   There is not enough information to tell.

Question 7

  • What is the purpose of a two-sample t test?


Answer

 

.   a.

To determine whether two means are more different than expected by chance.

 

.              b.

To compare the actual mean difference between groups with the difference desired by the researcher.

 

.   c.

To equate groups on one or more extraneous variables.

 

.   d.

To be twice as confident of your results as you would be in a one-sample t test.

 

             

Question 8

  • In a two-sample t test, if the observed difference between the sample means turns out to be one that would rarely occur when the null hypothesis is true, what should we do?


Answer

 

a.

.   Reject the null hypothesis.

 

b.

.   Retain the null hypothesis.

 

c.

.   Repeat the test until we get a more probable difference between the sample means.

 

d.

.   Change the level of significance (type 1 error).

10 points  

Question 9

  • Suppose that a researcher decides that he must obtain a type 1 error level of no more than 0.01 to reject the null hypothesis. After analyzing his data he finds that the results are significant at p = 0.05 but not at p = 0.01. If he is not able to change the maximum allowed type 1 error level, then the researcher should


Answer

 

.        a.

.           Retain the null hypothesis because 0.05 is greater than 0.01.

.          

.        b.

.           Retain the null hypothesis because 0.05 is merely sampling error.

.          

.        c.

.           Reject the null hypothesis because 0.05 is close to 0.01.

.          

.        d.

.           Reject the null hypothesis because 0.05 is greater than 0.01.

Question 10

  • What is the purpose of the change in formula from an independent sample t test to a related sample t test?


Answer

.          

.        a.

To simplify the calculation process when samples are dependent.

.          

.        b.

.           To remove the unwanted correlation introduced by the dependence of subjects between the IV conditions.

.          

.        c.

.           To remove the influence of unwanted or outlier cases in each sample.

.          

.        d.

To weight the contribution of each sample by the number of cases present in that sample.

 

Question 1

  • If the overall F is statistically significant, at least one pair of means must also be statistically significant.


Answer

True

False

Question 2

  • F can never be negative.


Answer

True

False

Question 3

  • One drawback of ANOVA is that it allows type 1 error to escalate for every additional group tested.


Answer

True

False


Question 4

  • If a study has 3 groups of 25 subjects each, the degrees of freedom are 2 and 24.


Answer

True

False

Question 5

  • All F values are positive.


Answer

True

False

Question 6


  In ANOVA, where should you look for the treatment effect?


Answer

 

. In the within-group variance.

.   In the between-group variance.

.   In the total variance.

.   Within a single individual's score.

Question 7

  • When and why would you conduct post hoc tests as a follow up to the overall F test?


Answer

 

.        a.

When the overall F test is NOT significant; to determine which of the pairs of groups may be significant.

 

.        b.

When the overall F test is NOT significant; to determine why the overall F test is not significant.

.       

.        c.

.              When the overall F test is significant; to determine between which pairs of groups the significant difference lies.

.       

.        d.

When the overall F test IS significant; to determine if the significance is only the result of chance.

  • Question 8
  • We use an F test rather than a t test for multi-group studies primarily to



Answer

.  

.   a.

.   Avoid calculating standard deviations from the variances.


.  

.   b.

.   Be able to use a single formula regardless of differing sample sizes between groups.


.  

.   c.

.   Reduce calculation time.


.  

.   d.

.   Avoid escalating type 1 error rates.


Question 9

  • The appropriate statistic to use when testing the hypothesis for a study with three treatment groups is a


Answer

.  

.   a.

.   One-sample t test.

.  

.   b.

.   Two-sample t test.

.  

.   c.

.   ANOVA F test.

.  

.   d.

.   Either b or c is appropriate.

 

Question 10

  • When the null hypothesis is true, the calculated F should be close to



Answer

.  

.   a.

.   0.


.  

.   b.

.   1.


.  

.   c.

.   Infinity.


.  

.   d.

.   There is not enough information to tell.


 

 

 

 

Question 1

  • To be statistically significant, Pearson's r should be greater than 0.90.


Answer

True

False


Question 2

  • The relative frequencies in the cells of a 2 × 2 table can be evaluated with a phi coefficient.


Answer

True

False

Question 3

  • The scatterplot for a positive relationship will graph from the upper left to the lower right.


Answer

True

False

Question 4

  • When scores vary in the same direction on two variables, the relationship is positive.


Answer

True

False

Question 5

  • For a Pearson's r, both variables must be linear.


Answer

True

False

Question 6

  • To compute a Pearson r correlation coefficient, we must have


Answer

 

a.

.            

.           A pair of scores for one individual.

 

.           b.

.            

.           A single set of scores for a single group of individuals.

 

.           c.

.            

.           Scores on two different variables for a single set of individuals.

 

.           d.

.            

.           Scores on two different variables for two different groups of individuals.

Question 7

  • In a correlational study, there is/are _______ group(s) of subjects, and each subject is measured on _______ variable(s).


Answer

.  

.   a.

.   1, 1.

.  

.   b.

.   1, 2.

.  

.   c.

.   2, 1.

.  

.   d.

.   2, 2.

10 points  

Question 8

  • The two variables in a correlational study are called the


Answer

.  

.   a.

.   Predictor and predicted.

.  

.   b.

.   Predictor and criterion.

.  

.   c.

.   Independent and dependent.

.  

.   d.

.   Relator and relatist.

Question 9

  • In a scatter diagram, if one of the points does not fall on the straight line of best fit to the data points, then r cannot be


Answer

 

.        a.

0.

.          

.        b.

+1.00 or -1.00.

 

.          

.        c.

   Positive.

.          

.        d.

Negative.

 

Question 10

  • A study reports: r(95) = +0.92, p < 0.01. How confident can you be that the obtained correlation is real and not due to mere chance?



Answer

.  

.   a.

.   92% confident.


.  

.   b.

.   95% confident.


.  

.   c.

.   99% confident.


.  

.   d.

.   There is not enough information to

 

 

STATS QUIZES 6,7,8,10
7442

Use the following directions to complete the attached assignment

- Describe the information provided by the Standard Deviation.

- Use the Standard Deviation to calculate the percentage of occurrence of a variable either above or below a particular value.

- Describe a normal distribution as evidenced by a bell shaped curve.

- Prepare a distribution chart from a set of data.

ASSIGNMENT #3:

  1. To get the best deal on a CD player, Tom called eight appliance stores and asked the cost of a specific model. The prices he was quoted are listed below
    $ 218 $ 125 $ 381 $ 187 $ 231 $ 213 $ 309 $ 230

    Find the Standard deviation

 

  1. When investigating times required for drive-through service, the following results (in seconds) were obtained. Find the range, variance, and standard deviation for each of the two samples, then compare the two sets of results.

    Wendy's 110 113 133 198 124 120 154 110
    McDonald's 105 116 131 176 118 110 135 137

 

  1. A company had 74 employees whose salaries are summarized in the frequency distribution below. Find the standard deviation. Find the standard deviation of the data summarized in the given frequency distribution.

    Salary Number of Employees
    5,001 -10,000 11
    10,001 - 15,000 13
    15,001 - 20,000 20
    20,001 - 25,000 17
    25,001 - 30,000 13

 

  1. The heights of a group of professional basketball players are summarized in the frequency distribution below. Find the standard deviation:

    Height (in.) Frequency
    70-71 4
    72-73 9
    74-75 18
    76-77 11
    78-79 9
    80-81 4
    82-83 1

 

ASSIGNMENT #3
7441

Using Excel, prepare a frequency distribution from the data you collected in the attachment.

- Calculate the Standard Deviation of your data and answer the following questions below.

- Is this a normal distribution?

- What are the implications?

SLP 3 - FREQUENCY
7439
  1. 49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively. Identify which type of sampling is used and why
  2. The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag. Identify which type of sampling is used and why
  3. An education expert is researching teaching methods and wishes to interview teachers from a particular school district. She randomly selects ten schools from the district and interviews all of the teachers at the selected schools. Does this sampling plan result in a random sample? Simple random sample? Explain.
  4. A polling company obtains an alphabetical list of names of voters in a precinct. They select every 20th person from the list until a sample of 100 is obtained. They then call these 100 people. Does this sampling plan result in a random sample? Simple random sample? Explain.
  5. The personnel manager at a company wants to investigate job satisfaction among the female employees. One evening after a meeting she talks to all 30 female employees who attended the meeting. Does this sampling plan result in a random sample? Simple random sample? Explain.

 Use information from the modular background readings as well as any good quality resource to complete the attached assignement. Please cite all sources and provide a reference list at the end of your paper. 

The following items will be assessed in particular: 

1.    Ensure that you are able to draw the proper inferences about the population after the sample has been evaluated. 

2.    Ensure that the process of selecting and evaluating a sample.

MOD 4 CASE: SAMPLING
7436

Use information from the modular background readings as well as any good quality resource you can find. Please cite all sources and provide a reference list at the end of the paper. Continue to collect data for five days and respond to the questions below with a brief summary for each: 

- Is the larger sample changing anything?

- Is your mean increasing or decreasing?

- Do you think the current sample you have is enough to paint an accurate picture, or do you need a much larger sample?

MAT 201 - SLP #4 (SAMPLING)
7434
  1. Find the equation of the regression line for the given data. What is the predicted value of Y when X = -2? What is the predicted value of Y when X = 4?

    X      -7      -2     5     1     -1     -2      0     2     3     -3

    Y     -12     -8     9     1     -5     -6     -1     4     7     -8
  2. The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Find the equation of the regression line for the given data. Predict the final exam score for students who studied 4 hours. Predict the final exam score for students who studied 6 hours.

    Hours (X)        3      5      2       8      2      4      4      5     6      3

    Score (Y)       75    90    70     98    76    88    95    99    98    81
  3. Find the correlation coefficient between X and Y. Is there a weak or strong, positive or negative correlation between X and Y?

    X     -5     -3     4     1     -1     -2     0     2     3     -4

    Y     -9     -7     8     2     -3     -5     -2     4     7    -7
  4. A pharmaceutical company tested two new flu vaccines intended to boost immunity. In order to test the effectiveness of this drug, a one year study was done were at the beggining of the year three groups of eight individuals were given either Flu Shot 1, Flu Shot 2, or a placebo (a shot with only saline and no vaccine). The number of sick days from work each individual took was carefully recorded over the following year. Both flu shots were found to be completely safe with no side effects, but differed in terms of effectiveness. The data below gives the number of sick days for the individuals in each of the three groups.

Perform a one-way ANOVA analysis, testing at the 0.05 level. Also, calculate the mean number of sick days for each group. Describe your results. But equally important, also explain what you would do if you owned your own company. Would you pay for your employers to receive Flu Shot 1 or Flu Shot 2 in order to keep their number of sick days down? If so, which one would you choose? Would you choose either vaccine only if it was very cheap or would you be willing to invest a lot into the vaccine for your employees? Explain your reasoning.

Group                     Sick days per year

Placebo        7     4     6     8    6     6     2    9

Flu Shot 1     5     3     3     5    4     7     3    3

Flu Shot 2     2     4     1     2    2    1     2     5

Submit your work by the module due date, if you are having difficulty please contact your professor.

 

Use information from the modular background readings as well as any good quality resource you can find. Please cite all sources and provide a reference list at the end of your paper.

The following items will be assessed in particular:

  1. Your ability to explain the limitations of the linear regression method.
  2. Your ability to describe ANOVA and identify when the ANOVA method should be used.
  3. Your ability to describe the correlation analysis and identify when the coefficient of correlation should be calculated.
  4. Your ability to identify when the Least Squares method should be used.
Stats case 5 anova
7433

For this assignment use regression to complete the assignment below:

Use information from the modular background readings as well as any good quality resource you can find. Please cite all sources and provide a reference list at the end of your paper.

The following items will be assessed in particular:

  1. Identify when the Least Squares method should be used.
  2. Describe ANOVA and identify when the ANOVA method should be used.

Take your data and arrange it in the order you collected it. Count the total number of observations you have, and label this number N. Then create another set of data starting from one and increasing by one until you reach N. For example, if you have 10 observations, then your new set of data would be (1, 2, 3, 4, 5, 6, 7, 8, 9, 10). This set of data is called a time series. Run a regression using your original set of data as your dependent variable, and your time series as an independent variable. Use the simple regression calculation page to calculate your regression. Write a paper reporting your results and any conclusions that can be reached with it.

MOD 5 SLP - ANOVA & Least Squares
7424

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