AP Statistics Sampling Distribution

Find μ_x-bar and σ_x-bar if μ = 794, σ = 48, and n = 64

• μ_x-bar = 794, σ_x-bar = 0.75

• μ_x-bar = 12.4, σ_x-bar = 0.75

• μ_x-bar =794, σ_x-bar = 6

• μ_x-bar = 99.25, σ_x-bar = 6

The normal approximation of a binomial can be used if

• n ≥ 10

• p ≥ 30

• np ≥ 5 or nq ≥ 5

• np ≥ 10 and nq ≥ 10

The mean weight of potato chip bags is 10.5 ounces with a standard deviation of 3 ounces. A random sample of 40 bags of potato chips is selected. What is the probability that the mean of the sample is less than 10 ounces? Use normcdf.

• P = -0.0509

• P = .1459

• P = .0202

• P = .8541

Of all cars on the highway, 80% are speeding. If we take a random sample of 50 cars, what is the probability that more than 90% will be speeding? Use normcdf.

• P = 0.000

• P = 0.0384

• P = 0.9615

• P = 1.3421

According to a recent poll, 92% of Americans believe more could be done to end the pandemic. Let's assume this is the parameter value for the population. If you take an SRS of 65 Americans and let p̂ = the proportion in the sample who feel more could be done, is the shape of the sampling distribution of p̂ approximately Normal?

• Yes, because n ≥ 30

• Yes, because np = 59.8

• No, because n(1-p) = 5.2

• No, because 65 ≤ 1/10 N

What does the symbol represent?

• standard deviation from a sample

• standard deviation from a population

• mean of the sampling distribution of sample proportions

• mean of the sampling distribution of sample means

• standard deviation of the sampling distribution of sample means

What does the symbol represent?

• mean from a sample

• mean from a population

• proportion from a population

• mean of the sampling distribution of sample means

• proportion from a sample

Here's a challenge... M is the median from a population, and m is the median of a sample taken from that population, what would the following symbol represent?

• mean of the sampling distribution of population medians

• standard deviation of the sampling distribution of population medians

• mean of the sampling distribution of sample medians

• standard deviation of the sampling distribution of sample medians

Here's a challenge... M is the median from a population, and m is the median of a sample taken from that population, what would the following symbol represent?

• mean of the sampling distribution of population medians

• standard deviation of the sampling distribution of population medians

• mean of the sampling distribution of sample medians

• standard deviation of the sampling distribution of sample medians

Review!

• exact y-value

• predicted y-value

• y-value from a sample

• y is Mrs. Keelen making us do this?