Show:
Catching Z's
Z Marks the Spot
Are You Ready for Area?
The Real World
Applying The Percentage Rule
100
The formula that converts a data point over to the standard normal distribution so that we can use the z table?
What is z = (x - mean) / std deviation
100
If the population mean is 30 and the population 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

A normal distribution has a mean of 8 and a standard deviation of 2. The value that is 2 positive standard deviations away from the mean is this.

What is 12?

200
Using z scores (or the z table) is appropriate for data with this shape
What is normal or bell-shaped data
200
If the z-score for x=28 is -.5 and the population standard deviation is 8, what is the population mean?
What is 32?
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 probability that you will wait more than 30 minutes for the ride.
What is .048 ?
200

A normal distribution has a mean of 15 and a standard deviation of 3. The value that is 3 negative standard deviations away from the mean is this.

What is 6?

300
The mean and standard deviation of the standard normal distribution?
What is mean = 0 and standard deviation = 1?
300
Find the z-score for which 20% of the area lies to the left.
What is .84 ?
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 is the probability that more than 170 cars go through the drive-thru today?
What is .0475
300

A normal distribution has a mean of 10 and a standard deviation of 1. The percentage of data values that fall between the values of 8 and 12 is this.

What is 95%?

400
Use the standard normal distribution to find P(z<-1.5 OR z>2).
What is .0896 ?
400
Find the z-score for which 10% of the data lies to the right.
What is 1.28 ?
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 is the probability that a cup is refilled?
What is .002 ?
400

A normal distribution has a mean of 24 and a standard deviation of 6. 68% of the values of this distribution fall between what two data values?

What is 18 and 30?

500
Tells us how many standard deviations above or below the mean a data value is.
What is a z-score?
500
Find the z-scores for which 96% of the distribution's area lies between -z and z.
What is 2.05 and -2.05?
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

A normal distribution has a mean of 100 and a standard deviation of 10. The percentage of data values that fall between the values of 70 and 90 is this.

What is 15.85?