Solution:
Given equation is .
To solve the equation by step by step.
Step 1: Given
Step 2: Combine like terms together.
Plus symbol changed to minus when the term goes from right to left (or) left to right of the equal sign.
Step 3: Subtract the fractions in the left side.
⇒
Step 4: Divide both side of the equation by 3, we get
Hence, the answer is .
Answer:
So then the minimum sample to ensure the condition given is n= 38
Step-by-step explanation:
Notation
represent the sample mean for the sample
population mean (variable of interest)
represent the population standard deviation
n represent the sample size
ME = 4 the margin of error desired
Solution to the problem
When we create a confidence interval for the mean the margin of error is given by this formula:
(a)
And on this case we have that ME =4 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
The critical value for 96% of confidence interval now can be founded using the normal distribution. The significance is . And in excel we can use this formula to find it:"=-NORM.INV(0.02;0;1)", and we got
, replacing into formula (b) we got:
So then the minimum sample to ensure the condition given is n= 38