ALL QUESTIONS
For each of the following, (a) say which populations are being compared,(b) state the research Hypothesis,(c)state the null hypothesis,(d) say whether you should use a one or two tail test and why
1-Do Canadian children whose parents are librariansscore higher the Canadian children in general on reading ability?
2-is the level of income for residents of a particular city different from the level of income for people in the region?
3-Do people who have experience and earthquake have more or less self-confidence then the general population?
For each of the following samples that were given an experimental treatment,
test whether they are different from the general population: (a) a sample of 10
with a mean of 44, (b) a sample of 1 with a mean of 48. The general population
of individuals has a mean of 40, a standard deviation of 6, and follows a normal
curve. For each sample, carry out a Z test using the five steps of hypothesis testing
with a two-tailed test at the .05 significance level, and make a drawing of the
distributions involved. (c) ADVANCED TOPIC: Figure the 95% confidence
interval for parts (a) and (b).
In each of the following studies, a single sample’s mean is being compared to a
population with a known mean but an unknown variance. For each study, decide
whether the result is significant. (Be sure to show all of your calculations.)`
Practice Problems
Estimated
Sample Population Population Sample Significance Level
Size (N ) Mean ( ) Variance ( ) Mean (M) Tails ( )
(a) 64 12.40 9.00 11.00 1 (low predicted) .05
(b) 49 1,006.35 317.91 1,009.72 2 .01
(c) 400 52.00 7.02 52.41 1 (high predicted) .01
1) For each of the following studies, say whether you would use a t test for dependent means or a t test for independent means.
a) A researcher randomly assigns a group of 25 unemployed workers to receive a new job skills program and 24 other workers to received the standard job skills program, and then measures how well they all do on a job-skills test.
b)A researcher measures self-esteem in 21 students before and after taking a difficult exam
c)A researcher tests reaction time of each of a group of 14 individuals twice, once while in a very hot room and once while in a normal-temperature room.
