CCSS.Math.Content.HSS.ID.A.4

The z-score represents.....

• the amount of standard deviations a data value is above or below the mean.
• the percentile the data value is above or below the mean.
• the amount of standard deviations a data value is above or below the median.
• the percent the data value is above or below the mean.

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CCSS.Math.Content.HSS.ID.A.4

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%
• 34%
• 16%
• 2.5%

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CCSS.Math.Content.HSS.ID.A.4

The mean GPA of students in a course at UCDavis is 3.2 with a standard deviation of 0.3. What percent of students in the course have a GPA between 2.9 and 3.8? 

• 81.85%
• 47.5%
• 68%
• 95%

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CCSS.Math.Content.HSS.ID.A.4

These symbols represent the mean and standard deviation for which of the following distributions?

• The Population
• The Sample
• The Sampling Distribution

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CCSS.Math.Content.HSS.ID.A.4

The positive standard deviations on a normal distribution curve mean what?

• Below average

• Above average

• Average

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CCSS.Math.Content.HSS.ID.A.4

The mean and standard deviation of a population are 400 and 40, respectively. Sample size is 25. 
What is the standard error of the sampling distribution?

• 400
• 40
• 25
• 8

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CCSS.Math.Content.HSS.ID.A.4

State whether you would use the central limit theorem or the normal distribution:
In a study done on the life expectancy of 500 people in a certain geographic region, the mean age at death was 72 years and the standard deviation was 5.3 years.
If a sample of 50 people from this region is selected, and the probability that the mean life expectancy will be less than 70 years.

• Central Limit Theorem
• Normal Distribution

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CCSS.Math.Content.HSS.ID.A.4

28% of all Woodrow students believe Monday will be snow day. You take a sample of 50 students and find that 15 of them believe Monday will be a snow day. (The sample proportion is 15/50 or .3) What is the probability of getting a sample of size 50 that has 15 or more students who believe Monday will be a snow day?

• 0.376

• Cannot be determined because the distribution of the sample proportion of samples of size 50 is not normal

• 0.624

• 0.99999

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CCSS.Math.Content.HSS.ID.A.4

A manufacturer of cell phone batteries claims that the average number of recharge cycles for its batteries is 400. A consumer group will obtain a random sample of 100 of the manufacturer’s batteries and will calculate the mean number of recharge cycles. Which of the following statements is justified by the central limit theorem?

• The distribution of the number of recharge cycles for the sample is approximately normal because the population mean of 400 is greater than 30.

• The distribution of the number of recharge cycles for the sample is approximately normal because the sample size of 100 is greater than 30.

• The distribution of the number of recharge cycles for the population is approximately normal because the sample size of 100 is greater than 30.

• The distribution of the sample means of the number of recharge cycles is approximately normal because the sample size of 100 is greater than 30.

• The distribution of the sample means of the number of recharge cycles is approximately normal because the population mean of 400 is greater than 30.

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CCSS.Math.Content.HSS.ID.A.4

The mean weight of a bag checked in at Southwest Airlines is 36 pounds with a standard deviation of 3.5 pounds. If two random bags were checked, what is the mean and the standard deviation of the weights of the two bags?

• 36, 4.95

• 36, 7

• 72, 4.95

• 72, 7

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CCSS.Math.Content.HSS.ID.A.4