the quality control manager at a computer manufacturing company believes that the mean life of a computer is 99 months, with a standard deviation of 8 months. if he is correct, what is the probability that the mean of a sample of 69 computers would be less than 97.94 months? round your answer to four decimal places.



Answer :

The probability that the mean of a sample of 78 computers would be less than 97.94 months exists 0.883.

What is meant by probability?

A probability is a numerical representation of the likelihood or chance that a specific event will take place.

Let the given values be

[tex]\mu[/tex] = 99, [tex]$\sigma[/tex] = 8

Let x be the random variable that represents the life of a computer.

Sample size: n = 69

Then, the z-score corresponds to x = 97.94 will be :-

[tex]$z=\frac{97.94-99}{\frac{8}{\sqrt{69}} \quad[\because} \quad z=\frac{x-\mu}{\left.\frac{\sigma}{\sqrt{n}}\right]}$[/tex]

z = -1.10062

Required probability ( using standard z-value table ) :-

P(x < 97.94) = P(z < -1.10) = 1 - P(z < 1.10)

= 1 - 0.1170 = 0.883

Therefore, the probability that the mean of a sample of 78 computers would be less than 97.94 months exists 0.883.

To learn more about probability refer to:

https://brainly.com/question/13604758

#SPJ4