Standard Normal Distribution Characteristics
What is the total area in the bell shape curve ?
1 or 100%
What z score matches up with the probability 0.0606
-1.55
Find the area to the left of z = 1.52
0.9357
What are the two ways the central limit theorem could work?
1. n >= 30
2. Original distribution is normal
What are the variables and what do they stand for?
n = # of trials
r = # of successes
p = prob of success
q = prob of success
Between u-o and u-2o, what percentage of our data fall?
77.5
Find the z where 67% of the data lies to the left of
0.44
Let x=7, mu=6 and o=1.2. Find the z score
0.83
How do you convert the x distribution equations (mu and sigma) to x bar distributions?
mu = mu and o = o/sqrt(n)
Probability of success is p; probability of failure is (blank) and is found by?
q and 1-p = q
Between u-o and u+o, what percentage of our data falls?
68%
Find the z score that will have 43% of the data lie to the right
0.18
Suppose your z score is equal to 1.43. Find the area to the right of that.
0.0764
What is the difference between a normal distribution and a x bar distribution?
x bar is looking at a mean of so many where x is looking at one
If given an r value, what do you have to do to convert it to an x value?
Add or subtract 0.5
Between u-2o and u+3o, what percentage of our data falls?
97.35
Find z and -z that will have 72% of the data fall between it
-1.08 and 1.08
Which formula is used to change an x value back to a z score?
x= u+zo
Let x bar=11, mu=12.1 and your adjusted sigma=0.54. Find the z score
-2.04
Let n=4 p=0.30 q=0.70. Find the mu and sigma
mu = 1.2 sigma = 0.92
Which is false or a normal curve?
1. mu is directly in the center of the curve
2. the curve crosses below the x-axis
3. the curve is symmetrical and mound shape
2
A kitten whose weight is in the bottom 10% of the distribution is considered undernourished. What is the cutoff point for the weight of an undernourished kitten?
mu = 24.5 and sigma = 5.25
Let x be between 10 and 26 with mu = 15 and sigma = 4. Find the probability of the area between.
0.8914
Let mu = 75 and normal sigma = 0.8. What is the probability that 20 cars chosen at random will have a mean load weight of less than 74.5 tons of coal?
0.0026
About 60% of costumers will take free samples according to a study. Today you are offering samples to 317 people. What is the probability that more than 180 will take your free sample?
0.8665