1if Selecting Samples Of Size N

1.if selecting samples of size n = 10 from a population with a known mean and standard deviation what requirement, if any must be satisfied in order to assume that the distribution of the sample means is a normal distribution
The population must have a normal distribution.
2. find the area of the shaded region. The graph depicts that standard normal distribution with mean 0 and standard deviation 1.
M: 0 δ: 1
Z: 1.13= .8708
2ND DIST. #2
LOWER: -999999
UPPER: 1.13
U: 0 δ: 1
=.8707618393

3. Shaded area is 0.0694
0.0694
-1
= -.9306 = 1.48 get this by looking at z score area on the chart

4. shaded area is 0.0901
0.0901
-1
= -1.34

5. Find the indicated Z score. The graph depicts the standard normal distribution with mean 0 and standard deviation 1. shaded are is 0.4013
2nd dist. #3
Area: 0.4013
U: 0 δ: 1
= -.24998 rounded to -0.25

6. If Z is a standard normal variable, find the probability.
The probability that Z lies between 0.7 and 1.98
2nd dist. #2
LOWER: .7
UPPER: 1.98
U: 0 δ: 1
= .2181

7. find the area of the shaded region. The graph depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15.
2nd dist. #2
LOWER: 85
UPPER: 125
U: 100 δ: 15
= .79355 = .7936

8. SOLVE THE PROBLEM. ROUND TO THE NEAREST TENTH UNLESS INDICATED OTHERWISE.
Scores on an English test are normally distributed with a mean of 33.8 and a standard deviation of 8.5. Find the score that separates the top 59% from the bottom 41%
2nd dist. #3
AREA: .41
U: 33.8 δ: 8.5
= .31.865

9. find the indicated Probability.
The diameters of bolts produced by a certain machine are normally distributed with a mean of 0.30 inches and a standard deviation of 0.01 inches. What percentage of bolts will have a diameter greater than 0.32 inches?
P(x>.32)
2nd dist. #2
LOWER: .32
UPPER: 999999
U: .30 δ: .01
= .022750062 =.0228 MOVE DECIMAL TO THE RIGHT 2 PLACES TO GET THE PERCENTAGE 2.28%

SOLVE THE PROBLEM
10. the amount of snow