AP Statistics · Topic 5.4
Biased and Unbiased Point Estimates Practice
Part of Sampling Distributions.(UNC-3.E)
Practice questions
9
Sample questions
5 of 9 — sign in to practice the rest with adaptive difficulty and mastery tracking.
Sample 1difficulty 1/5
Which symbol denotes the population standard deviation?
- A
σ̂
- B
σ_x̄
- C
s
- Dcheck_circle
σ
Why
σ is the population standard deviation; s denotes the sample standard deviation.
- A
Sample 2difficulty 1/5
A random sample of 50 voters is taken from a city, and 32 of them favor a new ordinance.
The value 32/50 = 0.64 is best described as which of the following?
- A
A statistic, x̄
- B
A parameter, p
- C
A parameter, μ
- Dcheck_circle
A statistic, p̂
Why
Because 0.64 was computed from a sample, it is a statistic — specifically the sample proportion p̂.
- A
Sample 3difficulty 1/5
Which symbol denotes the population proportion?
- A
P_x̄
- B
p̂
- Ccheck_circle
p
- D
π̂
Why
p denotes the population proportion; p̂ is the sample proportion.
- A
Sample 4difficulty 2/5
A statistic T is being evaluated as an estimator for a parameter θ.
Which statement best describes an unbiased estimator?
- Acheck_circle
The mean of its sampling distribution equals the parameter being estimated.
- B
Its sampling distribution is symmetric.
- C
Its standard deviation is small.
- D
It always equals the parameter.
Why
An estimator is unbiased when the mean of its sampling distribution equals the population parameter.
- A
Sample 5difficulty 2/5
A researcher computes the average height of all 1,200 students at a high school and finds it to be 65.4 inches.
Which symbol best represents the value 65.4 inches?
- A
x̄
- B
p
- Ccheck_circle
μ
- D
p̂
Why
Because every student in the population was measured, 65.4 inches is a parameter — the population mean μ.
- A