Question

How do women try to save when shopping for groceries? A sample of 1,008 adult women in the U. S. revealed that 937 women buy store brands, 837 women use print coupons, 726 women plan meals around sale items, and 333 women buy groceries online. (Data extracted from “Grocery Savings Habits of the American Woman,” Consumer Reports, October 2014, p. 11.)

1. For each way women try to save when shopping for groceries, construct a 95% confidence interval estimate of the population proportion.
2. What conclusions can you reach concerning how adult women in the U. S. try to save when shopping for groceries?

Provide steps

Answer 1

Solution:-

a) 95% confidence interval estimate of the women buy store brands is C.I = ( 0.9138, 0.9454).

C.I = 0.9296 + 1.96 × 0.0080595

C.I = 0.9296 + 0.0158

C.I = ( 0.9138, 0.9454)

b) 95% confidence interval estimate of the women use print coupons is C.I = ( 0.8072, 0.8536).

C.I = 0.8304 + 1.96 × 0.01182

C.I = 0.8304 + 0.02317

C.I = ( 0.8072, 0.8536)

c) 95% confidence interval estimate of the women plan meals around sale items is C.I = ( 0.6925, 0.7480).

C.I = 0.72024 + 1.96 × 0.014138

C.I = 0.72024 + 0.0277

C.I = ( 0.6925, 0.7480)

d) 95% confidence interval estimate of the women buy buy groceries online is C.I = ( 0.3014, 0.3594).

C.I = 0.3304 + 1.96 × 0.014814

C.I = 0.3304 + 0.02904

C.I = ( 0.3014, 0.3594)