stats Q pool 2

The average running speed of a high school athlete is 15 mph with a standard deviation of 2 mph. Mike runs at 18 mph. What is Mike's z-score, and is his speed unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=1.5z = 1.5, not unusual

• z=1.5z = 1.5, unusual

• z=2.0z = 2.0, unusual

• z=2.5z = 2.5, unusual

The average daily screen time for teenagers is 6.5 hours with a standard deviation of 1.2 hours. Jenny spends 9.4 hours on her phone daily. What is her z-score, and is it unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.42z = 2.42, unusual

• z=2.50z = 2.50, unusual

• z=2.25z = 2.25, not unusual

• z=3.00z = 3.00, unusual

The mean weight of newborns is 7.5 pounds with a standard deviation of 1.1 pounds. A baby weighs 5.2 pounds. What is the z-score for this weight, and is it unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=-2.09z = -2.09, unusual

• z=-1.91z = -1.91, not unusual

• z=-2.10z = -2.10, unusual

• z=-1.75z = -1.75, not unusual

A class has a mean test score of 80 and a standard deviation of 5. Lily scored 90 on the test. What is her z-score, and is her score unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.00, not unusual

• z=1.80, not unusual

• z=2.00, unusual

• z=2.50, unusual

The average height for adult males is 70 inches with a standard deviation of 3 inches. If Mark is 76 inches tall, what is his z-score, and is it unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.0, unusual

• z=2.5, unusual

• z=1.5, not unusual

• z=3.0, unusual

The average daily water consumption for a household is 250 gallons with a standard deviation of 30 gallons. The Smith family uses 310 gallons in a day. What is their z-score, and is it unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.00, not unusual

• z=2.00, unusual

• z=2.25, unusual

• z=1.75, not unusual

The average temperature in a city during July is 85°F with a standard deviation of 4°F. One day, the temperature reaches 95°F. What is the z-score, and is it unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.25z = 2.25, unusual

• z=2.50z = 2.50, unusual

• z=2.00z = 2.00, not unusual

• z=2.10z = 2.10, unusual

The mean time for students to finish a test is 50 minutes with a standard deviation of 8 minutes. Sarah finishes the test in 65 minutes. What is her z-score, and is her time unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=1.88z = 1.88, not unusual

• z=2.00z = 2.00, unusual

• z=1.75z = 1.75, not unusual

• z=2.10z = 2.10, unusual

The average weight of a pack of rice is 2 pounds with a standard deviation of 0.1 pounds. A pack weighs 2.3 pounds. What is its z-score, and is it unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.50z = 2.50, unusual

• z=3.00z = 3.00, unusual

• z=2.00z = 2.00, unusual

• z=2.75z = 2.75, unusual

The mean salary for employees at a company is $50,000 with a standard deviation of $4,000. A new employee earns $58,000. What is their z-score, and is this salary unusual? (In this case, assume unusual means more than 2 deviations above or below the mean)

• z=2.00z = 2.00, unusual

• z=2.25z = 2.25, unusual

• z=2.50z = 2.50, unusual

• z=1.75z = 1.75, not unusual