Suppose that a company claims that its batteries last 250 hours on average. it took many large samples, and each time the mean number of hours was outside the 95% confidence interval. based on this information alone, which of the following is probably not the mean number of hours that the company's batteries last?

a. 240
b. 245
c. 250
d. 235

C. 250

Step-by-step explanation:

Confidence interval is used to express the degree of uncertainty associated with a sample statistic.

The confidence interval is calculated as,

As here the confidence interval is 95%, we shall use .

So the confidence interval will be,

And

As it is given that, each time the mean number of hours was outside the 95% confidence interval, it will be either below or above 250.

Therefore, the value can be anything, but not 250.

b

step-by-step explanation:

given

- 2 (3x + 12y - 5 - 17x - 16y + 4 )

simplify the parenthesis by collecting like terms

= - 2 (- 14x - 4y - 1) ← distribute the parenthesis by - 2

= 28x + 8y + 2 → b

d

step-by-step explanation: