Consumer Reports indicated that the average life of a refrigerator before replacement is 14 years with a standard deviation of 2.5 years. Assume the age a refrigerator is replaced is normally distributed. A.) State the random variable
B.) What is the probability that someone will keep a refrigerator fewer than 11 years before replacement?
C.) What is the probability that someone will keep a refrigerator more than 18 years before replacement?
D.) What is the probability that someone will replace a refrigerator between 8 and 15 years?
E.) Suppose a company guarantees refrigerators and will replace a refrigerator that breaks while under guarantee with a new one. However, the company does not want to replace more than 5% of the refrigerators under guarantee. For how long should the guarantee be made (rounded to the nearest tenth of a year)?
F.) If it turns out that 40$ of all new refrigerators need to be replaced withing 10.5 years, is there an issue with the manufacturing process? Have some numbers to back up your reasoning.

a.) Average life of a refrigerator

b.) 0.1151

c.) 0.0548

d.) 0.6472225

Step-by-step explanation:

Given that :

Average life before replacement, mean, m = 14 years

Standard deviation, σ = 2 years

A.)

The random variable is the variable which is being measured.

B.) What is the probability that someone will keep a refrigerator fewer than 11 years before replacement?

Fewer than 11 years, P(x < 11)

We need to obtain the Z probability, at P(Z < 11)

The Zscore = (x - mean) / standard deviation

Zscore = (11 - 14) / 2.5 = - 1.2

P(Z < - 1.2) = 0.1151

C.) What is the probability that someone will keep a refrigerator more than 18 years before replacement?

More than 18 years, P(x > 18)

We need to obtain the Z probability, at P(Z > 18)

The Zscore = (x - mean) / standard deviation

Zscore = (18 - 14) / 2.5 = 1.6

P(Z > 1.6) = 0.0548

D.) What is the probability that someone will replace a refrigerator between 8 and 15 years?

P(x < 8)

The Zscore = (x - mean) / standard deviation

Zscore = (8 - 14) / 2.5 = - 2.4

P(Z < - 2.4) = 0.0081975

P(x < 15)

The Zscore = (x - mean) / standard deviation

Zscore = (15 - 14) / 2.5 = 0.4

P(Z < 0.4) = 0.65542

P(Z < 0.4) - P(Z < - 2.4)

0.65542 - 0.0081975 = 0.6472225

4+n=5

step-by-step explanation:

this is because the four is four hours and the n represents the 1 extra hour over the weekend.

b= i'm srry i don't know that one.

4+n=5 n=1 because if vernon plays 5 hours a week then 4+1=5 hours.

hope this : )

answer: there are x+184 pages in olivia's book.

step-by-step explanation:

let the total number of pages in the book which olive has already read be x.

then if olive has 184 pages left to read, then the total number of pages are in olive's book= pages she has read+pages she has left to read

therefore, the total number of pages in olivia's book=

hence, there are x+184 pages in olivia's book.