A new version of SAT is given to 1000 randomly selected high school seniors. Thesample mean test score is 1110, and the sample standard deviation is 123. Constructa 95% confidence interval for the population mean test score for high school seniors.

(1108.49 ; 1111.56)

Explanation:

confidence interval.

Sample mean (S) = 1110

Sample Size (N) = 1000

standard deviation (sd) = 123

confidence α= 1 - 0.95 = 0.05/2 = 0.025

Z distribution table

Zα= Z(0.025) = 0.4013

confidence interval

(S - Zα.×Sd/ ; S + Zα.×Sd/)

(1110 - 0.4013×(123/) ; 1110 + 0.4013×(123/)

(1108.491029 ; 1111.5608970091)

(1108.49 ; 1111.56)

answer: marginal utility of the fourth brownie is 0.

explanation: marginal utility is the addtional utility gained from the consumption of one more unit of a good. it is given by,

so, marginal utility at the 4th unit will be given by

since, the values are not given here, you can simply find marginal utility at fourth unit by subtracting total utility at 3rd unit from total utility at 4th unit.