Question

In what follows use any of the following tests/procedures: Regression, confidence intervals, one-sided t-test, or two-sided t-test. All the procedures should be done with 5% P-value or 95% confidence interval. Open Brain data. Claim: Male and female subjects have different total (brain) surface areas. 9. What test/procedure did you perform? a. One-sided t-test b. Regression c. Two-sided t-test d. ​​Confidence interval 10. What is the P-value/margin of error? a. 0.450365624 b. 1.10877E-11 c. 0.435460528 d. 0.900731248 e. ​​None of these 11. Statistical interpretation a. The 95% confidence interval does not contain the averages. b. Since P-value is too large we cannot conclude that the two variables have different averages. c. Since P-value is too large we cannot claim that there is connection between two variables. d. Since P-value is small we can claim that there is connection between two variables. e. None of these 12. Conclusion a. Yes, I am confident that the averages are different. b. No, I cannot claim that the average are different.

Answer 1

To test the claim Male and female subjects have different total (brain) surface areas,

9)

Correct Answer: c. Two-sided t-test

Explanation:

Since we are comparing two sample's (Male and female ) total (brain) surface areas 2 sample t statistic will be used to test whether the population means of total (brain) surface areas are equal for both Male and female

10)

Correct Answer: e. ​​None of these

Explanation:

The P-value for two sided t test is obtained as follow,

From the data values, the mean and average for both the samples are,

	Male	Female
	1806.31	1913.88
	2018.92	1902.36
	2154.67	2264.25
	1767.56	1866.99
	971.63	1743.04
	1689.6	1684.89
	2136.37	1860.24
	1966.81	2216.4
	1827.92	1850.64
	1773.83	1709.3
mean	1811.362	1901.199
sd	335.7145	195.8892
n	10	10

The test statistic is obtained using the formula,

Since n_1 = n_2 = n = 10, the formula reduced to,

Now, the P-value is obtained from t distribution table for degree of freedom = n_1+n_2-2 = 18.

11)

Correct Answer: b. Since P-value is too large we cannot conclude that the two variables have different averages

Explanation:

The P-value = 0.4742 is greater than 0.05 at 5% significance level, we cannot conclude that there is different in averages.

12)

Correct Answer: a. Yes, I am confident that the averages are different.

Explanation:

Since there is sufficient statistical evidence we cannot reject the null hypothesis.