Amarketing consultant observed 40 consecutive shoppers to estimate the average money spent by shoppers in a supermarket store. assume that the money spent by the population of shoppers follow a normal distribution with a standard deviation of $21.51. what is the probability that the average money spent by a sample of 40 shoppers is within $10 of the actual population mean.

0.998 is the probability that the average money spent by  a sample of 40 shoppers is within $10 of the actual population mean.

Step-by-step explanation:

We are given the following information in the question:

Standard Deviation, σ = $21.51

We are given that the distribution of average money spend is a bell shaped distribution that is a normal distribution.

Formula:

We have to find:

P( average money spent is within $10 of the actual population mean.)

Calculation the value from standard normal z table, we have,  

99

step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18