A company offering online speed reading courses claims that students who take their courses show a 5 times (500%) increase in the number of words they can read in a minute without losing comprehension. A random sample of 100 students yielded an average increase of 415% with a standard deviation of 220%. Calculate a 95% confidence interval for the average increase in number of words students can read in a minute without losing comprehension. Choose the closest answer.

C.I = (371.88  , 458.12)

Step-by-step explanation:

Given that:

sample size n = 100

sample mean 415

standard deviation = 220

The objective is to calculate the  95% confidence interval for the average increase in number of words students who can read in a minute without losing comprehension.

At 95% confidence interval; level of significance ∝ = 1 - 0.95

level of significance ∝ = 0.05

The critical value at is 1.96

C.I =

C.I =

C.I =

C.I =

C.I =

C.I =

C.I = (371.88  , 458.12)

step-by-step explanation:

we are given

since, we have to isolate x on anyone side

so, we can move all x terms on one side

subtract both sides by 2x

add both sides by 9

divide both sides by 4

we get

so what is the problem what are they asking you to solve

step-by-step explanation:

so what is the problem what are they asking you to solve