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Terms and Conditions
Probability
The Normal Curve
Central Limit Theorem
Normal Models
100
This statistic describes the center of the normal distribution.
What is the mean?
100
The probability a value will fall within 2 standard deviations of the mean.
What is .95?
100
99.7% of the data in a normal model is between these two z-scores.
What is -3 and 3?
100
The mean of the sample distribution is equal to this.
What is the mean of the population?
100
The shape of a normal model.
What is bell shaped and symmetric?
200
This statistic describes the spread of a normal distribution.
What is the standard deviation?
200
The probability a value has a z-score less than 1.25
What is .894?
200
The times that represent the middle 50% of sleeping times of medical residents at a hospital, assuming sleeping times can be approximated with a normal model with a mean of 6.1 hours and a standard deviation of 1 hour.
What are 5.43 hours and 6.77 hours?
200
The sample size required when the estimated proportion of successes is .333
What is greater than or equal to 30?
200
The descriptive statistics that are equal in a normal model.
What are the mean, median, and mode?
300
The rule that states what percent of the data is between 1, 2 or 3 standard deviations.
What is the Empirical Rule or 68-95-99.7% Rule?
300
The percent of students that scored between 18 and 25 on the ACT English exam, which follows a normal model with a mean of 20.6 and a standard deviation of 6.3.
What is 41.8%?
300
The z-score associated with the highest 20% of values in a normal model.
What is .841?
300
An estimate of the standard deviation found by using the sample proportion and sample size.
What is the standard error?
300
A normal model with a mean of 0 and standard deviation of 1.
What is the standard normal distribution?
400
This statistic is the number of standard deviations a value is away from the mean.
What are z-scores?
400
The probability of getting an SAT Writing score greater than 600, if the SAT Writing Test follows a normal model with a mean of 493 and a standard deviation of 111.
What is .168?
400
The z-score and exact value of the 93rd percentile of the annual per capita consumption of fresh apples in the US, when the annual per capita consumption of apples (in pounds) can be modeled by a normal distribution with a mean of 16.2 pounds, and a standard deviation of 4 pounds.
What are 1.476 and 22.1 pounds?
400
A study found that green turtles have a mean migration distance of 2200 kilometers and a standard deviation of 625 kilometers. If the migration times of turtles follow a normal model, the mean and standard deviation of the sample distribution is this when a sample of 12 turtles is taken.
What is 2200 kilometers and 180.4 kilometers?
400
The area under the normal curve.
What is 1?
500
A distribution that is formed when samples are taken from a population.
What is a sampling distribution?
500
The number of men out of a sample of 250, who have a cholesterol level less than 225 mg per dL of blood, if cholesterol levels of men follow a normal model with a mean of 209 mg/dL and a standard deviation of 37.8 mg/dL.
What is 166 men?
500
The standard deviation of the normal model that approximates the length of armadillos with a mean length of 30 inches, when 15% of all armadillos are over 43 inches long.
What is 12.54 inches?
500
The mean value of land and buildings per acre for farms is $1300. A sample of 36 farms is randomly selected. Assume the standard deviation is $250 dollars. This is the probability that the mean value of land and buildings per acre is between $1150 and $1400.
What is .992
500

The symbols for population mean and population standard deviation.

What are µ (mu) and σ (sigma)?