The shape of the distribution of the time required to get an oil change at a 10 minute oil change facility is unknown. However, records indicate that the mean time is 11.2 minutes and the standard deviation is 4.8 minutes (a) to compute probabilities regarding the sample mean using the normal model, what size sample would be required?
(b) What is the probability that a random sample of n=45 oil changes results in a sample mean time less than 10 minutes?

The answer is below

Step-by-step explanation:

a) For a normal model the sample size has to be equal or greater than 30 so that it can be a normal distribution.

b) Given that:

μ = 11.2 minutes, σ = 4.8 minutes, n = 45

The z score determines how many standard deviations the raw score is above or below the mean. It is given by:

For x < 10 minutes

Therefore from the normal distribution table, P(x < 10) = P(z < -1.68) =  0.0465

3,6 and 7.

step-by-step explanation:

a) unit place of 37 is 7

so the unit place of cube of 37 will be

7³= 343=3

the answer is 3.

b) unit place of 56 is 6, so the unit place of cube of 56 will be

6³= 216=6

the answer is 6.

c) unit place of 133 is 3, so the unit place of cube of 133 will be

3³= 27= 7.

the answer is 7.