Lab Assignment 5
For each of the following situations determine whether a one- or two-tailed test is appropriate. Please circle the correct answer:
You are interested in finding out if the average household income of residents in your state is different from the national
average household. According to the census, for 2010, the national average household income is $50,303.
a) one-tailed
b) two-tailed
c) either will do.
A sociologist believes that the average income of elderly women is lower than the average income of elderly men.
a) one-tailed
b) two-tailed
c) either will do.
Is there a difference in the amount of study time on-campus and off-campus students devote to their schoolwork during an
average week?
a) one-tailed
b) two-tailed
c) either will do.
Reading scores for a group of third graders enrolled in an accelerated reading program are predicted to be higher than the
scores for non-enrolled third graders.
a) one-tailed
b) two-tailed
c) either will do.
The 2008 GSS of the American adult population found a mean age of 39.2 and a standard deviation of 17.35 for a selected
sample of 400 adults. Assume that we know from census data that the mean age of all American adults is 37.7. Use this
information to answer the following question. Show your work in as much detail as possible.
One-tailed test
State the research and the null hypotheses in statistical notation.
Calculate the t statistic and test the null hypothesis at the .05 significance level.
Do you reject the null hypothesis?
What conclusion(s) do you draw as a result of the hypothesis test?
Two-tailed test
State the research and the null hypotheses in statistical notation.
Calculate the t statistic and test the null hypothesis at the .05 significance level.
Do you reject the null hypothesis?
What conclusion(s) do you draw as a result of the hypothesis test?
The 2008 GSS data showed that the average educational attainment for liberals is 13.90 years (Sy1=3.27) and the average
educational attainment for conservatives is 13.55 (Sy2=2.82). Data are based on 187 liberals and 277 conservatives.
Assuming unequal variances in the two subpopulations perform a two-tailed test to find out if there is a difference in level of
education between liberals and conservatives.
State the research and the null hypotheses in statistical notation.
at the .05 significance level (95% confidence level).
Do you reject the null hypothesis?
What conclusion(s) do you draw as a result of the hypothesis test?
The following questions require the use of SPSS. Please use 2012 GSS data to conduct tests for the following research
questions.
Please attach your SPSS output to your assignment.
Whether the mean of the age when the first child was born (agekdbrn) is significantly different from the national average age
in 1970 (21.4).
Whether the average TV watching hours per day (tvhours) for men is significantly different from the average hours of women.