stat meth business wang

If a set of data is approximately normally distributed, we would find that approximately 2 of every 3 observations would fall between ± 1 standard deviation around the mean. 4 of every 5 observations would fall between ± 1.28 standard deviations around the mean. 19 of every 20 observations would fall between ± 2 standard deviations around the mean. All other options are correct.

All

The standard error of the mean decreases as the sample size increases. measures the variability of the mean from sample to sample. All others are correct is never larger than the standard deviation of the population.

All others are correct

In the construction of confidence intervals, if all other quantities are unchanged, an increase in the sample size will lead to an________ interval.

Narrower

In perfectly symmetrical distributions, which of the following is NOT a correct statement? The distance from Q1 to Q2 equals to the distance from Q2 to Q3. The distance from the smallest observation to Q1 is the same as the distance from Q3 to the largest observation. The distance from the smallest observation to Q2 is the same as the distance from Q2 to the largest observation. The distance from Q1 to Q3 is half of the distance from the smallest to the largest observation.

The distance from Q1 to Q3 is half of the distance from the smallest to the largest observation.

Which of the following statements about the sampling distribution of the sample mean is incorrect? The standard deviation of the sampling distribution of the sample mean is equal to the population standard deviation σ . The sampling distribution of the sample mean is approximately normal whenever the sample size is sufficiently large ( n ≥ 30 ). The mean of the sampling distribution of the sample mean is equal to μ . The sampling distribution of the sample mean is generated by repeatedly taking samples of size n and computing the sample means.

The standard deviation of the sampling distribution of the sample mean is equal to the population standard deviation σ .

In general, which of the following descriptive summary measures cannot be easily approximated from a boxplot? The variance The range The interquartile range The median

The variance

If the expected value of a sample statistic is equal to the parameter it is estimating, then we call that sample statistic ______ . minimum variance. random. biased. unbiased.

Unbiased

The Central Limit Theorem is important in statistics because

for a large n, it says the sampling distribution of the sample mean is approximately normal, regardless of the shape of the population.