This has more conceptual questions because I think they’re important Be sure to understand the

Question: #8958

This has more conceptual questions, because I think they’re important. Be sure to understand the
2x2 box dealing with Type I and Type II errors, alpha, beta, and power.
Each multiple choice questions is worth 0.50 point. Other questions are worth two points.
1. (0.50 point) I hypothesized that girls in my class have the same blood pressure levels as boys.
The probability value for my null hypothesis was 0.15. So I conclude that the blood pressures of
the girls were higher than boys’. Which kind of mistake did I make?
a. Type I error
b. Type II error
c. Type I and Type II error
d. I did not make any mistake
2. (0.50 point) If a statistical test result is not significant at the 0.05 level, then we can conclude:
a. It is not significant at 0.10 level
b. It must be significant at 0.01 level
c. It must be significant above 0.05 level
d. It is not significant at 0.01 level
3. (2 points) A researcher posed a null hypothesis that there was no significant difference
between boys and girls on a standard memory test. She randomly sampled 100 girls and 100
boys in a community and gave them the standard memory test. The mean score for girls was 70
and the standard deviation of mean was 5.0. The mean score for boys was 65 and the standard
deviation of mean was 5.0. What is the standard error of the difference in means?

4. (0.50 point) If power is big, you can assume:

a. The significance level set by the researcher must be high
b. We increase the probability of type I error
c. Your study result will be more likely to be inconclusive
d. The difference between the means is more likely to be detected
5. (0.50 point) If the probability that you will correctly reject a false null hypothesis is 0.80 at
0.05 significance level. Therefore, α is__ and β is__.
a. 0.05, 0.80
b. 0.05, 0.20
c. 0.95, 0.20
d. 0.95, 0.80

6. (2 points) The population has a mean of 678 and the population standard deviation is
known to be 58.3. Use a 0.05 level of significance to test the claim that the sample scores
listed below came from the population. Identify hypotheses, test statistic, P-value or
critical value, conclusion about the null, and final conclusion that addresses the original
claim.
714
698

751
836

664
753

789
834

818
693

779
802

7. (2 points) I am looking to move to either Mississippi or Arkansas, depending on the cost
of housing. Below are the costs (in thousands, hypothetically) of 12 houses in each
location based upon a simple random selection:
Mississippi:
138
Arkansas:
137

155
161
133
143

142

149

130

151

163

151

142

156

133

140

142

131

134

129

128

140

140

140

Use a 0.05 significance level to test the claim that the mean cost of houses in Mississippi
is greater than the mean cost in Arkansas. Be sure to give the hypotheses, the test statistic
with a p-value, and a conclusion.