An admissions director wants to estimate the mean age of all students enrolled at a college. the estimate must be within 1.3 years of the population mean. assume the population of ages is normally distributed.(a) determine the minimum sample size required to construct a 90% confidence interval for the population mean. assume the population standard deviation is 1.5 years.

4

Step-by-step explanation:

For given Population standard deviation , the formula to sample size is given by :-

, where z* = Two-tailed critical value.

E = Margin of error.

Given : years

We know that , Critical value for 90% confidence interval : z* = 1.645

Margin of error : E=1.3 years

Then, the minimum sample size required to construct a 90% confidence interval  for the population mean will be :-

[Rounded to the nearest whole number.]

Hence, the minimum sample size required = 4

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

a

step-by-step explanation:

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