Question

 

list of vehicles and their horsepower. These are:

211    230    182    155   320   310   320   140

177    138    306    310   171   169   150

a) Find the mean and standard deviation of the horsepower data.

b) Draw a normal probability plot (QQ plot) for the horsepower data

c) Draw a histogram of the horsepower data.

d) Using the actual data, find the number of cars with horsepower higher than the first car listed (211 hp). Then divide by 15 to get a percent

e) Using normalcdf, find the percent of cars with more horsepower than the first car listed (211 hp).

f) Compare your results of parts d and e. Are they close?

g) Do the data appear normal? Explain using parts b ,e and f

please answer only e, f, and g questions  !! thanks

here is A to D answers

Answers B

A) If the observations are

X1,X2,X3,X4,X5…………X15

Mean= 219.3

Std=72.9

B) A normal probability plot is created using Minitab

C) The Histogram of the horsepower data is created using Minitab

X represent horsepower

D) Number of cars with horsepower higher than first car listed(2011hp)=6

Percent=6/15*100=40%

Answer 1

e) Using normalcdf, find the percent of cars with more horsepower than the first car listed 211 hp

i.e.

i.e. P(X > 211) = 0.5453

f) Compare your results of parts d and e.

From Part (D), probability = 0.40 i.e. 40%

but from Part(e), probability = 0.5453 i..e 54.53%

It is not closed to each other

g) since the data is not appear to normal distribution since curve is not bell shaped from histogram and the points are not showing as the straight line in probability plot and probabilities are not equal in both cases i.e. part (a) and (b) so the given data is not normal distribution.