7. A 95% confidence interval is required for the difference between the average credit card balance for card with rewards points and cards without rewards points. I wish you to restrict your analysis to only standard type credit cards as Low interest cards do not qualify for rewards points.

a. Write out a Levene's test to establish whether the population variances can be assumed equal in this case.

b. Write out the appropriate 95% confidence interval for the difference between the average credit card balance for card with rewards points and cards without rewards points using the correct notation.

c. Interpret the confidence interval in context.

d. Show that the necessary conditions hold for the confidence interval to be valid.

The data:

Group Statistics Std. Error Rewards N Mean Std. Deviation Mean 3mm w No 298 $1,705.15 5937.039 554.281 Independent Samples Test Levene's Test for Equality of Variances t-test for Equality of Means 95% Confidence Interval of the Mean Std. Error Difference F Sig. Difference Difference Lower Upper Balance Equal variances 6.772 009 $96.103 $77.505 $56.071 $248.277 assumed Equal variances not $96.103 $76.146 -$53.408 $245.614 assumedSimple Histogram of Balance by Rewards (Palkhi Kapadia) 30 20 Frequency Percent 10 0 Rewards 30 20 Yes Frequency Percent 10 0 $0 $1,000 $2,000 $3,000 $4,000 $5,000 $6,000 Balance