CRIMJ 260 - EXAM 4 QUESTIONS AND
ANSWERS
A group of social scientists wanted to determine if police officers have a higher IQ than
the general public. To test this theory, they took a sample of 140 police officers and
administered an IQ test. The mean score for officers was 112 with a standard deviation
of 10. A second sample of 150 citizens from the general population yielded an average
IQ score of 105 with a standard deviation of 15. Utilize the t-statistic to test the following
hypotheses:
Ha: Police Officers are significantly more intelligent than the general public
Ho: Police officers are not significantly more intelligent than the general public
What is the calculated value of t for this problem? - Answer-4.68
A group of social scientists wanted to determine if police officers have a higher IQ than
the general public. To test this theory, they took a sample of 140 police officers and
administered an IQ test. The mean score for officers was 112 with a standard deviation
of 10. A second sample of 150 citizens from the general population yielded an average
IQ score of 105 with a standard deviation of 15. Utilize the t-statistic to test the following
hypotheses:
Ha: Police Officers are significantly more intelligent than the general public
Ho: Police officers are not significantly more intelligent than the general public
What conclusion is most appropriate given the data? - Answer-Police Officers are
significantly more intelligent than the general population.
Suppose you are interested in the relationship between adolescent employment and the
number of delinquent acts one commits. To examine this relationship, you take a
sample of 30 youths, 10 of whom did not work in the previous year, 10 youths who
worked less than 15 hours per week during the previous year, and 10 youths who
worked more than 15 hours per week during the previous year. Each of the 30 youths in
the sample was asked to self-report the number of different delinquent acts they have
committed from a list of possible offenses. The resulting data are presented in the table
below:
Nonworkers Moderate Workers Intensive Workers
7 10 11
12 14 8
13 8 7
5 7 10
899
11 11 9
10 13 7
14 12 8
983
683
Mean = 9.5 Mean = 10.0 Mean = 7.5
ANSWERS
A group of social scientists wanted to determine if police officers have a higher IQ than
the general public. To test this theory, they took a sample of 140 police officers and
administered an IQ test. The mean score for officers was 112 with a standard deviation
of 10. A second sample of 150 citizens from the general population yielded an average
IQ score of 105 with a standard deviation of 15. Utilize the t-statistic to test the following
hypotheses:
Ha: Police Officers are significantly more intelligent than the general public
Ho: Police officers are not significantly more intelligent than the general public
What is the calculated value of t for this problem? - Answer-4.68
A group of social scientists wanted to determine if police officers have a higher IQ than
the general public. To test this theory, they took a sample of 140 police officers and
administered an IQ test. The mean score for officers was 112 with a standard deviation
of 10. A second sample of 150 citizens from the general population yielded an average
IQ score of 105 with a standard deviation of 15. Utilize the t-statistic to test the following
hypotheses:
Ha: Police Officers are significantly more intelligent than the general public
Ho: Police officers are not significantly more intelligent than the general public
What conclusion is most appropriate given the data? - Answer-Police Officers are
significantly more intelligent than the general population.
Suppose you are interested in the relationship between adolescent employment and the
number of delinquent acts one commits. To examine this relationship, you take a
sample of 30 youths, 10 of whom did not work in the previous year, 10 youths who
worked less than 15 hours per week during the previous year, and 10 youths who
worked more than 15 hours per week during the previous year. Each of the 30 youths in
the sample was asked to self-report the number of different delinquent acts they have
committed from a list of possible offenses. The resulting data are presented in the table
below:
Nonworkers Moderate Workers Intensive Workers
7 10 11
12 14 8
13 8 7
5 7 10
899
11 11 9
10 13 7
14 12 8
983
683
Mean = 9.5 Mean = 10.0 Mean = 7.5
