The speeds of vehicles traveling on a highway are normally distributed with a population standard deviation of 7 miles per hour and an unknown population mean. if a random sample of 20 vehicles is taken and results in a sample mean of 60 miles per hour, find a 98% confidence interval for the population mean.

Step-by-step explanation:

Given : The speeds of vehicles traveling on a highway are normally distributed .

Standard deviation:

Since , sample size : , which is small sample (n<30) so the test applied here is a t-test.

Degree of freedom=

Sample mean :

Level of significance :

Then , significance level :

Using t-distribution table , Critical value :

The confidence interval for population mean is given by :-

Hence, a 98% confidence interval for the population mean=

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl

what do u need to know

step-by-step explanation: