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Catching Z's
Z Marks the Spot
Are You Ready for Area?
The Real World
Give Me a Sign
100

The formula for z-scores

What is z = (x - mean) / std deviation

100

If the mean is 30 and the standard deviation is 7.5, change 42 into a z-score.

What is 1.6

100
Find the area under the standard normal curve to the left of z=-1.23
What is .1093 ?
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 20%

What is 0.84?

200

Using z scores is appropriate for data with this shape

What is normal or bell-shaped data

200

If the z-score for x=28 is -1 and the standard deviation is 8, what is the mean?

What is 36?

200
Find the area under the standard normal curve to the right of z=1.75.
What is .0401 ?
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?

300

The mean and standard deviation of the standard normal distribution. (HINT: What are the defaults in the DeltaMath calculator?)

What is mean = 0 and standard deviation = 1?

300

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 ?

300
Find the area under the standard normal curve between z=-1.2 and z=1.2.
What is .7698 ?
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?

400

Use the standard normal distribution to find the percentage between z=-1.5 and z=2

What is 91.04% ?

400

If the z-score for 30 is 2 and the mean is 18, what is the standard deviation?

What is 6 ?

400
Find the area under the standard normal curve between z=-2 and z=1.
What is .8185 ?
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

Find the z-scores for the middle 96%

What is -2.05 to 2.05?

500
Tells us how many standard deviations above or below the mean a data value is.
What is a z-score?
500

If the z-score for x=124 is 0.5 and the standard deviation is 12, what is the mean?

What is 118?

500
Find the area under the standard normal curve between z=1.05 and z=2.24.
What is .1344 ?
500
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?
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?