A dieter believes that the average number of calories in a homemade peanut better cookie is more than the average number of calories in a store-bought peanut better cookie. which excel statements will estimate the difference in mean calories between the two types of cookies using a 90% confidence interval. the data are: homemade store-bought sample size 40 45 mean number of calories 180 179 standard deviation 2 4

a. = (180-179) + (1.96) (0.6749), and = (180-179) - (1.96) (0.6749)

b. = (180-179) + (1.645) (0.6749), and = (180-179) - (1.645) (0.6749)

c. = (45-40) + (1.96) (0.6749), and = (45-40) - (1.96) (0.6749)

d. = (45-40) + (1.645) (0.6749), and = (45-40) - (1.645) (0.6749)

e. none of the above.

Question

Mathematics

Ellen Arroyo

17 February, 19:49

A dieter believes that the average number of calories in a homemade peanut better cookie is more than the average number of calories in a store-bought peanut better cookie. which excel statements will estimate the difference in mean calories between the two types of cookies using a 90% confidence interval. the data are: homemade store-bought sample size 40 45 mean number of calories 180 179 standard deviation 2 4

a. = (180-179) + (1.96) (0.6749), and = (180-179) - (1.96) (0.6749)

b. = (180-179) + (1.645) (0.6749), and = (180-179) - (1.645) (0.6749)

c. = (45-40) + (1.96) (0.6749), and = (45-40) - (1.96) (0.6749)

d. = (45-40) + (1.645) (0.6749), and = (45-40) - (1.645) (0.6749)

e. none of the above.

+5

Answers (1)

Know the Answer?

Keaton Owen · Answer 1

The confidence interval formula is computed by:

Xbar ± Z s / sqrt (n)

Where:

Xbar is the mean

Z is the z value

S is the standard deviation

N is the number of samples

So our given are:

90% confidence interval with a z value of 1.645

Sample size 40, 45

Mean 180, 179

Standard deviation 2, 4

So plugging that information in the data will give us a confidence interval:

For 1:

Xbar ± Z s / sqrt (n)

= 180 ± 1.645 (2 / sqrt (40))

= 180 ± 1.645 (0.316227766)

= 180 ± 0.520194675

= 179.48, 180.52

For 2:

Xbar ± Z s / sqrt (n)

= 179 ± 1.645 (4 / sqrt (45))

= 179 ± 1.645 (0.596284794)

therefore, the answer is letter b