A normal population has the mean of 10 and the variance of 25 . A random sample of size n-28 is selected. (a) Find the standard deviation of the sample mean. Round your answer to two decimal places (e.g. 98.76)
(b) How large must the sample be if you want to halve the standard deviation of the sample mean?

Step-by-step explanation:

Given that:

population mean = 10

variance = 25  ; = = 5

sample size n = 28

The standard deviation of the sample mean:

=

= 0.95

To halve the standard deviation of the sample mean, the size of how large the sample will be can be computed as follows:

= 2

n = 4 × 28

n = 112

F(x) = x³ - 7
f(x + 2) = (x + 2)³ - 7
f(x + 2) = (x + 2)(x + 2)(x + 2) - 7
f(x + 2) = (x(x + 2) + 2(x + 2))(x + 2) - 7
f(x + 2) = (x(x) + x(2) + 2(x) + 2(2))(x + 2) - 7
f(x + 2) = (x² + 2x + 2x + 4)(x + 2) - 7
f(x + 2) = (x² + 4x + 4)(x + 2) - 7
f(x + 2) = (x²(x + 2) + 4x(x + 2) + 4(x + 2)) - 7
f(x + 2) = (x²(x) + x²(2) + 4x(x) + 4x(2) + 4(x) + 4(2)) - 7
f(x + 2) = (x³ + 2x² + 4x² + 8x + 4x + 8) - 7
f(x + 2) = (x³ + 6x² + 12x + 8) - 7
f(x + 2) = x³ + 6x² + 12x + 8 - 7
f(x + 2) = x³ + 6x² + 12x + 1

g(x) = f(x + 2) + 4
g(x) = (x³ + 6x² + 12x + 1) + 4
g(x) = x³ + 6x² + 12x + 1 + 4
g(x) = x³ + 6x² + 12x + 5