Z-Scores
Draw a picture
Finding Percents
Inverse Norm
Mixed Practice
100
If the mean is 30 and the standard deviation is 7.5, change 42 into a z-score.
What is 1.6
100
The weights of cereal boxes are normally distributed with a mean of 14oz and SD of 0.2oz. Draw a diagram for boxes weighing between 14.2 and 14.5
100
Suppose the prices of a certain guitar are normally distributed with a mean of $159. What percentage of buyers would pay less than $150 if the standard deviation is $15?
What is 27.4% ?
100
Find the z-score for the top 15%
What is z=1.04?
100
Find the z-score for x=17 with a distribution of N(20, 4)
What is z=-0.75?
200
IQ scores are normally distributed with a mean of 97 and a standard deviation of 11. An individual's IQ score is found to be 110. Find the z-score corresponding to this value.
What is z=1.18 ?
200
Draw a picture of the bottom 50%
200
The length of time people wait to ride a roller coaster is normally distributed with a mean time of 20 minutes and a SD of 6 minutes. Find the percentage that you will wait more than 30 minutes for the ride.
What is 4.8% ?
200
Find the z score for the bottom 10%
What is z=-1.28?
200
Find the percentile for the top 20%
What is the 80th percentile?
300
If the z-score for x=28 is -1 and the standard deviation is 8, what is the mean?
What is 36?
300
Heights of adult females have an average of 162cm and a SD of 7.5cm. Draw a picture representing all females taller than 150cm.
300
The number of cars that go through the drive thru at Wendy's in a day is normally distributed with a mean of 120 and a SD of 30. What percentage of the days have more than 170 cars go through the drive-thru?
What is 4.75%
300
IQ scores are normally distributed with a mean of 97 and a standard deviation of 11. What score would you need to be in the top 15%?
What is 108?
300
The IQR is between which two percentiles
What is the 25th and the 75th?
400
If the z-score for x=124 is 0.5 and the standard deviation is 12, what is the mean?
What is 118?
400
Draw a picture of the 90th percentile.
400
The amount of coffee a machine dispenses is normally distributed with a mean of 11.8 oz and a standard deviation of .25 oz. When the machine dispenses more than 12.5 oz the cup must be refilled. What percentage of cups have to be refilled?
What is 0.2% ?
400
The amount of corn chips dispensed into a 48-ounce bag by the dispensing machine has been identified as possessing a normal distribution with a mean of 48.5 ounces and a standard deviation of 0.2 ounce. What chip amount represents the 67th percentile for the bag weight distribution?
What is 48.59 ounces?
400
Describe what it means to have a z-score of 1
What is you are 1 standard deviation above the mean?
500
If the z-score for 30 is 2 and the mean is 18, what is the standard deviation?
What is 6 ?
500
Draw a picture of the middle 50% of data
500
Heights of adult females have an average of 162cm and a SD of 7.5cm. Find the percent of all females taller than 150cm.
What is 95%
500
The number of cars that go through the drive thru at Wendy's in a day is normally distributed with a mean of 120 and a SD of 30. What is the interquartile range?
What is 40?
500
Find the z-scores for the middle 96%
What is -2.05 to 2.05?