Question

A set of laptop prices are normally distributed with a mean of 750 dollars and a standard deviation of 60
dollars.
What proportion of laptop prices are between 624 dollars and 768 dollars?!
You may round your answer to four decimal places.

Answer 1

Answer:

0.6

Step-by-step explanation:

Given: Mean= $750

          Standard deviation= $60

First, lets find out z-score of the interval between $624 and $768.

z score= $\frac{x-mean}{Standard deviation}$

z score= $\frac{624-750}{60}= \frac{-126}{60}$

∴ z score for $624 is -2.1

Now, finding z score for $768

Z score= $\frac{768-750}{60} = \frac{18}{60}$

∴ z score for $768 is 0.3

As per the z score table, the value for -2.1 is 0.0179 and for 0.3 is 0.6179

Now, subtracting the value to get proportion

$0.6179-0.0179= 0.6$

∴ There are 0.6 proportion of laptops are in the range of $624 and $768

         

Answer 2

Answer:

0.6

Step-by-step explanation:

it is right