Empirical Rule
The percentage of data located within 1 standard deviation of the mean.
What is 68%
If the population mean is 30 and the population standard deviation is 7.5, change 42 into a z-score.
What is 1.6
Area to the left of z = 1.32
What is .9066
The z-score that corresponds to the cumulative area on the left of 0.3520.
What is -.38?
A binomial distribution with a sample size of 20 and a probability of 60%.
What is NO!
The percentage of data located within 2 standard deviations of the mean.
What is 95%
If the mean is 10, and the standard deviation is 2, this is the z-score of an observation of 12.5
What is 1.25?
Area to the right z = -0.63
What is .7357
Find the z-score for which 10% of the data lies to the right.
What is 1.28 ?
A binomial distribution with a sample size of 200 and a probability of 15%.
What is YES
This is the percentage of data to the left of the mean.
What is 50%
Let's say the average IQ of a group of people is 105 with a standard deviation of 15. This is the z-score of someone with an IQ of 93?
What is -0.8?
P(-2.46 < z < 1.75)
What is 0.9530
Find the z-score for which 20% of the area lies to the left.
What is -0.84 ?
A binomial distribution with a sample size of 25 and a probability of 66%.
What is NO
This is the percentage of data outside of 3 standard deviations of the mean.
What is 0.3%
The ACT has an average score of 18 with a standard deviation of 6. A student scores a z-score of 2.1. This is her actual score.
What is 30.6?
Find the area under the curve that lies within one standard deviation from the mean.
What is .6826 (or 68%)
Find the z-score for which 56% of the data lies to the right.
What is -0.15?
A binomial distribution with a sample size of 14 and a probability of 75%.
What is NO
If the average score on the PBR was 84 with a standard deviation of 8, what percentage of students scored below a 76?
What is 16%
If the z-score for x=28 is -0.5 and the population standard deviation is 8, what is the population mean?
What is 32?
Find the area for P(z < .46) or P(z > 2.85)
What is 0.6794
Find the z-score for which 72% of the data lies to the left.
What is 0.58?
A binomial distribution with a sample size of 36 and a probability of 36%.
What is YES