Unit 4 II Maths stat

The mean of the sampling distribution of the sample mean is:

• Always zero

• Equal to population mean

• Greater than population mean

• Sample variance

The standard deviation of the sampling distribution is called:

• Variance

• Mean deviation

• Standard error

• Sampling bias

As sample size increases, the standard error:

• Increases

• Decreases

• Remains constant

• Becomes zero

The standard error of the sample mean is:

• σ

• σ/√n

• √σ

• nσ

The larger the sample size, the:

• Less reliable the results

• Greater the variability

• Smaller the standard error

• Larger the standard error

A statistic is:

• A population parameter

• A function of sample observations

• Always equal to the mean

• Population data

A sampling distribution becomes normal when:

• Sample size is large (Central Limit Theorem)

• Population is small

• Variance is zero

• Mean is zero

Large sample tests are applicable when:

• n < 30

• n ≥ 30

• n = 10

• n ≤ 10

In large samples, the test statistic for mean is based on:

• Student's t-distribution

• F-distribution

• Z-distribution

• Poisson distribution

For two large independent samples with means x̅₁, x̅₂ the test statistic is:

• Z=x̅₁ + x̅₂ / σ

• Z = x̅₁ - x̅₂ / √(σ₁²∕n₁ + σ₂²∕n₂)

• Z = x̅₁ - x̅₂

• Z = σ₁ + σ₂