Question

Using our Class Survey data, Prof. Denice was interested in testing whether students’ confidence in their abilities (even when faced with challenges) is related to their expected undergraduate grade average upon completion of their bachelor’s degree. There are a number of reasons to expect that these would be related: Students who are more confident in their abilities may end up earning higher grades on average as compared to less confident students, or they may just also be more confident in their ability to earn higher grades.

To examine the relationship between students’ confidence and their expected grade average, Prof. Denice runs a regression analysis. But first, he combines some categories of the question, "How often is R confident in their abilities?" (see the codebook). Instead of the original 5 categories, students are grouped into the following 3 categories: 1=always/often, 2=sometimes, 3=rarely/never. The table below presents the results of Prof. Denice’s regression analysis.

Regression of expected grade average on confidence in abilities

Variable

Estimates

Confidence in abilities (ref.=always/often)

Sometimes

-1.338***

(0.346)

Rarely/never

-2.706***

(0.599)

Intercept

80.047***

(0.205)

N

1,779

R-squared

0.015

Notes: Standard errors are in parentheses. Statistical significance is indicated by: *p<.05, **p<.01, ***p<.001.

Question A.

What is the t-value for the regression coefficient on "rarely/never"? Round to the nearest 3 decimal places. If you do not have enough information to find this value, simply enter 0 in the space provided.

Question B.

What is your decision about the null hypothesis that there is no difference in the average expected grade among students who rarely/never have confidence in their abilities and the students who always/often have confidence in their abilities (at alpha=.05)?

A. Reject the null hypothesis. The difference between these two groups is statistically significant.

B. Reject the null hypothesis. The difference between these two groups is not statistically significant.

C. Accept the null hypothesis. The difference between these two groups is statistically significant.

D. Accept the null hypothesis. The difference between these two groups is not statistically significant.

E. Fail to reject the null hypothesis. The difference between these two groups is statistically significant.

F. Fail to reject the null hypothesis. The difference between these two groups is not statistically significant.

Answer 1

Question A.
The t-value for the regression coefficient on "rarely/never" is not provided in the information given. Please enter 0 in the space provided.

Question B.
Based on the information provided, we can make a decision about the null hypothesis. Looking at the regression analysis, the coefficient for "rarely/never" is statistically significant at the significance level of α = .05. This is indicated by the "***" symbol next to the coefficient estimate in the table.

Therefore, the decision about the null hypothesis is:
A. Reject the null hypothesis. The difference between these two groups is statistically significant.