1. Identify each of the following as examples of nominal, ordinal, interval, or ratio scales of measurement.

1. A poll of registered voters in Florida asking which candidate they support

 

Nominal                (Categorical, not ordered)

2. The length of time required for a wound to heal when using a new medicine
Ratio                      (Meaningful comparisons between values, and a true zero)

 

3. The number of telephone calls arriving at a switchboard per five-minute period
Ratio                      (Meaningful comparisons between values, and a true zero)

 

4. The distance first-year college football players can kick a ball
Ratio                      (Meaningful comparisons between values, and a true zero)

 

5. Mental health diagnoses present in an elderly population
Nominal                                (Categorical, not ordered)

 

6. The rankings of employees on their job performance
Ordinal                   (Categorical, and can be ordered)

 

 

2) Two hundred raffle tickets are sold. Your friend has five people in her family who each bought two raffle tickets. What is the probability that someone from her family will win the raffle?

 

P(win) = number of tickets purchased / number of tickets sold

 

P(win) = (5*2) / 200 = 10/200 = 1/20 = 0.05

3) Jolie has 45 minutes to do her statistics homework. If the mean is 38 minutes and the standard deviation is 3, calculate Jolie’s z score. Once calculated, interpret your findings in terms of Jolie’s performance.

 

Assuming that Jolie took all 45 minutes to complete her homework, her z score is:

 

 

This z score indicates that Jolie took longer to complete her homework than 99% of the students.

4) . A psychologist measures units of change for a memory test after students are given an opportunity to sleep only four hours. The following change units were obtained: 7, -12, 4, -7, 3, -10. Find the

 

a) mean:                                -2.5

 

b) median:                            -2

 

c) mode:                                                There is no mode for this data

 

d) standard deviation:        8.12

 

e) range:                                                19

 

f) variance:                           65.9
 

5) A student scored 81 on a chemistry test and 75 on a history test. For the chemistry test, the mean was 70 and the standard deviation was 20. For the history test, the mean was 65 and the standard deviation was 8. Did the student do better on the chemistry test or the history test? Explain your answer.

 

The z score for the chemistry test is:

 

 

The z score for the history test is:

 

 

The student did better on the history test, as his/her score was a greater number of standard

deviations above the mean for the history test.

 

6.             Problem #6 was not posted.

7. Variables in which the values are categories are known as)

Interval variables
Nominal variables
Ordinal variables
Ratio variables
 

8. Before the researcher can conduct a statistical test, the research question must be translated into
A testable hypothesis
Additional observations
Mathematical symbols
Numbers

9. The hypothesis stating that there are no differences, effects, or relationships is)
The alternative hypothesis
The baseline hypothesis
The null hypothesis
The reasonable hypothesis
 

10. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the mean score?
6.6
7.2
7.8
8.7
 

11. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the median score?
6
7
8
9
 

12. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the mode?
5
7
8
9

13. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the range of scores?
5
6
7
11
 

14. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the variance, treating these scores as a sample?
1.53
1.60
2.33
2.56

 

15. The standard normal distribution has all the following properties EXCEPT:)
The mean, mode, and median are all equal
The total area under the curve equals 1
The curve is specified by two parameters, the mean and the standard deviation
The curve extends to + and – 3 standard deviations from the mean
 

16. According to the Empirical Rule, approximately _______% of the data in a normal distribution will fall within ±1 standard deviation of the mean. (Points : 4)
34
68
95
99.7
 

17. In statistical computations, the number of values that are free to vary is known as (Points : 4)
Degrees of freedom
Freedom factor
Variability index
Variation quotient
 

18. Which of the following reflects a Type I error?
Rejecting the null hypothesis when in reality the null hypothesis is true
Rejecting the null hypothesis when in reality the null hypothesis is false
Accepting the null hypothesis when in reality the null hypothesis is true
Accepting the null hypothesis when in reality the null hypothesis is false

 

 

19. Which type of sampling is used when the experimenter asks 5 area doctors to refer pregnant women to his study and accepts all women who offer to be in his study?

 

purposive sampling

convenience sampling

cluster sampling

stratified sampling

 

 

20. In our statistics equations, n refers to:

mean

standard deviation

normal distribution

number of subjects

 

 

21. Which of the following is true regarding alpha?

 

it is also known as the level of significance
value is set by the researcher
value is equal to the probability of a type I error
all of the above are true

 

 

22. Macy proposes that boys who play sports are viewed as more attractive than boys who do not play sports. What is her null hypothesis?

 

Boys who play sports are not viewed as more attractive than boys who do not play sports
Playing sports will influence how attractively boys are viewed
Boys who play sports are more attractive than girls who play sports
There can be no null hypothesis

23. You calculate a t of 2.38 and note that the tabled value for .01 is 3.22 and for .05 is 2.19. You would conclude that the null hypothesis can be:

 

Accepted at the .05 level
Rejected at the .01 level
Rejected at the .05 level
None of the above

 

 

24. A researcher is studying political conservatism among 11 engineering students and 11 humanities students. The number of degrees of freedom for a t test is:

 

22
20
11
10
 

25. A t test for dependent groups should be used instead of a t test for independent samples:

 

If each participant is measured twice
Whenever there are equal numbers of subjects in each group
Whenever there are only two groups
All of the above

 

 

26. In a normal distribution, what percent of the population falls within one and two standard deviations of the mean?

 

34%
68%
95%
cannot tell from the information given

 

 

27. Which of the following is more affected by extreme scores?

Mode
Mean
Median
None of the above are affected

 

 

28. On a histogram, what does the vertical (y) axis refer to?

Individual scores
Frequencies
Means
Deviation scores

 

 

29. Which statistic refers to the average amount by which the scores in the sample deviate from the mean? Range
Standard deviation
Median
Mode

 

 

30. Assume a normal distribution for N = 300. How many cases would one expect to find between +1 and -1 standard deviations around the mean?

 

102
285
150
204

31. A z score of zero tells us that the score is at the________of the distribution.

Mean
Very top
Very bottom
None of the above since z cannot be zero

 

 

32. In a unit normal curve, what goes on the x axis?

Frequencies
Observed scores
z scores
Area

 

 

33. Which of the following is a measure of variability?

Mean
Range
Interval
All of the above

 

 

34. The only measure of central tendency that can be found for nominal data is the

Mean
Median
Mode
Midrange

 

 

35. If the probability of event A is 0.45 and the probability of event B is 0.35 and the probability of A and B occurring together is 0.25, then the probability of A OR B is:

0.8
1.8
0.1575
0.55

 

 

36. A researcher knows that the average distance commuting students live from campus was previously 8.2 miles. Because of the rising prices of gasoline, the research wants to test the claim that commuting students now live closer to campus. What is the correct alternative hypothesis?

 

The new mean distance is 8.2 miles.
The new mean distance is less than or equal to 8.2 miles.
The new mean distance is less than 8.2 miles.
The new mean distance is greater than or equal to 8.2 miles.