A manufacturer claims that its televisions have an average lifetime of at least five years (60 months) with a population standard deviation of seven months. Eighty-one televisions were selected at random, and the average lifetime was found to be With is the manufacturer's claim supported?

Step-by-step explanation:

The question is incomplete. The complete question is:

A manufacturer claims that its televisions have an average lifetime of at least five years (60 months) with a population standard deviation of seven months. Eighty-one televisions were selected at random, and the average lifetime was found to be 59 months.

a. Should z test or t test be used?

b. With a = 0.025, is the manufacturer's claim supported?

Solution:

a) The z test should be used because the population standard deviation is given.

b) We would set up the hypothesis test. This is a test of a single population mean since we are dealing with mean

For the null hypothesis,

µ ≥ 60

For the alternative hypothesis,

µ < 60

This is a left tailed test.

The z score would be determined from the normal distribution table. The formula is

z = (x - µ)/(σ/√n)

Where

x = sample mean

µ = population mean

σ = population standard deviation

n = number of samples

From the information given,

µ = 60

x = 59

σ = 7

n = 81

z = (59 - 60)/(7/√81) = - 1.29

Looking at the normal distribution table, the probability corresponding to the z score is 0.098

Since alpha, 0.025 < than the p value, 0.098, then we would fail to reject the null hypothesis. Therefore, At a 2.5% level of significance, we can conclude that the manufacturer's claim is supported.

answer: sorry

step-by-step explanation: can you tell me pls how to find the rational of two integers

the answer is:

the answer is:

to solve the problem, we need to remember the quotient of power property, it's defined by the following relation:

if we have a quotienf of powers that have the same base, we need to keep the same base and subtract the exponent of the denominator power to the exponent of the numerator power.

so, we are given the expression:

then, calculating we have:

hence, the answer is:

have a nice day!