An air conditioner service company records that the time (in hours) that a techn

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An air conditioner service company records that the time (in hours) that a technician requires to complete an air conditioner repair has a distribution that is strongly skewed right...

1. About? 75% of houng adult Internet users watch online video. Suppose that a sample survey contact an SRS of 1000 young adult Internet users and calculates the proportion in this sample who watch a Check that a Normal condition is met for the sampling distribution 000c. what is needed to assume that the sampling distribution is made up of independent samples? c. Describe the sampling distribution 1000-s i7 d. If the sample size were 9000 rather than 1000, how would the sampling distribution change? e. What is the probability that a sample size of 1000 has a p smaller than 55? An air conditi 2. oner service company records over many years show that the time (in hours) that a technician requires to complete an air conditioner repair has a distribution that is strongly skewed right with a mean of repair time being 1 hourand a standard deviation of 1 hour For planning purposes, the company will take a SRS of 140 repairs in the last year. a. Check that a Normal condition is met for the sampling distribution b. What is needed to assume that the sampling distribution is made up of independent samples? c. Describe the sampling distribution d. If the sample size were reduced from 140 to 70, how would the sampling distribution change? e. What is the probability that a sample size of 70 has a mean larger than 1.1 hours? 2

Explanation / Answer

Answer:

An air conditioner service company records that the time (in hours) that a technician requires to complete an air conditioner repair has a distribution that is strongly skewed right

a).

since the sample size 140 is greater than 30, by central limit theorem, the sampling distribution of mean approximately normally distributed.

b).

we have to assume that repair time of one air conditioner does not affect the other.

c).

The sampling distribution of mean follows approximately normally distributed with mean 1 hour and with standard deviation of 1/sqrt( 140) =0.0845.

d).

The sampling distribution of mean follows approximately normally distributed with mean 1 hour and with standard deviation of 1/sqrt( 70) = 0.1195.

e).

z value for 1.1, z =(1.1-1)/0.1195 =0.84

P( mean x >1.1) = P( z >0.84)

=0.2005

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