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Practice Problems Practice Problems 1 A

VIEWS: 20 PAGES: 5

									                                              Practice Problems

1) A population has a mean of 45 and a standard deviation of 5. Find the z-scores of the following raw
   scores:

       a) score = 47

       b) score = 48

       c) score = 40

       d) score = 39

2) A population has a mean of 45 and a standard deviation of 5. Find the raw scores of the following z-
   scores:

       a) z-score = 1.3

       b) z-score = -0.4

       c) z-score = 0

       d) z-score = -1.5

3) The following table shows the scores of subject 1 on six different scales of an aptitude test. Also shown
   are the means and standard deviations of these scales.

              Test                 Mean        Standard Deviation          Score               Z-Score
        Clerical Ability            50                 15                    41
      Logical Reasoning             40                  4                    47
      Mechanical Ability           120                 25                   100
     Numerical Reasoning           100                 10                   105
       Spatial Relations            70                 20                    90
        Verbal Fluency              60                  6                    70

   a) Calculate the z-scores for each.




   b) On which test did subject 1 score the highest? Which did subject 1 score the lowest?
                                               Practice Problems

4.) Convert the following test scores to z-scores and then decide which is the student’s best and worst area
    of performance.

   a) Best:___________________________________                  Worst:_____________________________

           Test                 Score                 Mean           Standard Deviation         Z-Score
    Oral Interpretation          38                    40                    10
       Persuasion                28                    20                    20
     Theory Building             45                    30                    20


   b.) Best:___________________________________                         Worst:________________________

          Test                  Score                Mean           Standard Deviation          Z-Score
        BUS 205                  60                   80                     8
        ECN 201                  92                   78                    15
        ECN 202                  85                   75                    10

5.) Convert the following test scores to z-scores and then decide which is the student’s best and worst area
    of performance.

   a) Best:________________________________                     Worst:_____________________________

          Test                  Score                Mean           Standard Deviation          Z-Score
         English                 87                   80                     5
         Science                 90                   92                    16
         History                 75                   55                    18


   b) Best:___________________________________                  Worst:_____________________________

          Test                  Score                Mean           Standard Deviation          Z-Score
        BUS 205                  38                   50                    18
        ECN 201                  28                   15                    21
        ACC 101                  45                   20                    16


   c) Best:___________________________________                  Worst:_____________________________

         Test                   Score                Mean           Standard Deviation          Z-Score
        CIS 100                  48                   35                    20
        WRT 100                  38                   22                    30
        BUS 100                  55                   19                    15
6.) Under regular circumstances the population of 2-year old children has an average weight of 26 lbs. The
    distribution of weights is normal with a standard deviation of 2. The researcher, who thinks that
    children will weigh more with extra handling, selects a random sample of n = 4 newborn infants,
    instructs the parents to provide each child with extra handling, and then records the weight of each child
    at age 2. The average weight of the sample is 29.5 lbs.

   a) What are the IV?_____________________________________ DV?_________________________


   b) What is the hypothesis (words)?_______________________________________________________


   c) What is the testable hypothesis (numerically)?___________________________________________


   d) What is the critical region? ____________________________________________________


   e) What is the z-test for this infant?____________________________________________________




   f) Graph the distribution, critical area, and shade in where the z-test needs to lie in order for the
      hypothesis to be proven true.




   g) Do you accept or reject the hypothesis?
                                        Z-Test Extra Practice Problems

7.) In each of the sections of BUS 205, the instructor handed out different study guides to see if different
    study guides would make a difference in students’ grades on the exam. All four sections of BUS 205’s
    test #1 were scored and the average for the first exam was a 75 across all sections with a standard
    deviation of 5. The instructor wanted to know if her section first section of BUS 205 was different from
    the population of BUS 205 students in her sections. The scores for the exam were as follows for section
    1: 75, 90, 85, 60, 55.


   a) What are the IV?_____________________________________ DV?_________________________


   b) What is the hypothesis (words)?_______________________________________________________


   c) What is the testable hypothesis (numerically)?___________________________________________


   d) What is the null hypothesis
      (words)?_____________________________________________________


   e) What is the null hypothesis
      (numerically)?________________________________________________


   f) What is the critical region? ____________________________________________________


   g) What is the z-test?____________________________________________________




   h) Graph the distribution, critical area, and shade in where the z-test needs to lie in order for the
      hypothesis to be proven true.




   g) Do you accept or reject the hypothesis?
8.) The HR department of DWE wanted to know if their orientation was helping managers better
    understand the rules of the company. The HR department knew that if an employee read the manual
    s/he would have a better understanding of company rules. Half of the managers participated in the
    orientation where they were given the manual to read and the other half of the mangers did not
    participate nor were they given a manual. The managers were then given a survey to see if they were
    able to answer different rules of the company. The following table is a listing of their scores.

                                     Managers in              Managers not in
                                     Orientation               Orientation
                                         75                        80
                                         63                        65
                                         88                        90
                                         69                        45
                                         72                        82

   a) What are the IV?_____________________________________ DV?_________________________


   b) What is the hypothesis (words)?_______________________________________________________


   c) What is the testable hypothesis (numerically)?___________________________________________


   d) What is the null hypothesis
      (words)?_____________________________________________________


   e) What is the null hypothesis
      (numerically)?________________________________________________


   f) What is the critical region? ____________________________________________________


   g) What is the z-test?____________________________________________________


   h) Graph the distribution, critical area, and shade in where the z-test needs to lie in order for the
      hypothesis to be proven true.




   g) Do you accept or reject the hypothesis?

								
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