Answer:
This statement can be made with a level of confidence of 97.72%.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 8.1 mm
Standard Deviation, σ = 0.5 mm
Sample size, n = 100
We are given that the distribution of thickness is a bell shaped distribution that is a normal distribution.
Formula:
Standard error due to sampling:

P(mean thickness is less than 8.2 mm)
P(x < 8.2)
Calculation the value from standard normal z table, we have,

This statement can be made with a level of confidence of 97.72%.
Answer:
0.74
Step-by-step explanation:
The standard deviation of a data set is the sqaure root of the variance, so first we must find the variance. The equation for variance is:
σ² = ![\frac{{(x_{1}-[x bar] )}^{2}+...+{(x_{n}-[x bar]) }^{2}}{n}](https://tex.z-dn.net/?f=%5Cfrac%7B%7B%28x_%7B1%7D-%5Bx%20bar%5D%20%29%7D%5E%7B2%7D%2B...%2B%7B%28x_%7Bn%7D-%5Bx%20bar%5D%29%20%7D%5E%7B2%7D%7D%7Bn%7D)
x = number in the data set
xbar = median of the data set
n = number of terms
Plugging in the given values, the equation for the variance of this number set is:
σ² = 
Solving:
= 
= 
σ² = 0.546875
Since the standard devianation is the sqaure root of the variance, we'll sqaure 0.546875:

= 0.73950997288745
= 0.74 (rounded)
hope this helps!
Answer:180
Step-by-step explanation:
I believe the answer is 59/10 or 5.9/10