Biostatistics Lesson 5

Which of the two measures of dispersion typically makes more "real world" sense? A. Standard Deviation B. Variance

A. It is standard deviation.

The difference between our sample estimate and the true population value is known as: A. Standard Error B. Mean Value C. Variance D. Standard Deviation

A. Standard error is a statistical term that measures the accuracy with which a sample represents a population.

We set a 95% confidence interval and calculate the estimated prevalence of diabetes in the population. Your research director would like you to calculate a 99% confidence interval instead. The width of the resulting interval at the 99% confidence level will be _______. A. Smaller B. Wider C. The same width

B. If you want more confidence that an interval contains the true parameter, then the intervals will be wider.

In conducting our experiment, we set our alpha level at 1% and find a resulting p-value of .04. Which of the following is the correct conclusion from the experiment? A. Reject the null hypothesis B. Fail to reject the null hypothesis C. Neither A nor B

B. We fail to reject the null hypothesis.

In an experiment, we set our alpha level at 5% and find a resulting p-value of .04. We conclude that we are unable to reject the null and have no evidence to support our alternative hypothesis. We have committed a: A. Type I Error B. Type II Error

B. We have committed a type II error. It is the failure to reject a false null hypothesis.

What measure is an indicator of the "peakedness" of a distribution? A. Median B. Mode C. Kurtosis D. Skewness

C. Kurtosis is an indicator of the "peakedness" of a distribution.

The measure used to describe how much a distribution is shifted to the left or the right (asymmetrically) is called.... A. Interquartile Range B. Standard Deviation C. Skewness D. Kurtosis

C. Skewness is the measure used to describe how much a distribution is shifted to the left or the right (asymmetrically).

The intended result of any experiment is formulated using the: A. Alternative Hypothesis B. Null Hypothesis

A. Alternative Hypothesis is used to formulate the intended result of any experiment.

The Type 1 error rate probability is derived from: A. Alpha B. Sample size C. Power D. Critical Value E. T-statistic

A. Type 1 error rate probability is derived from alpha.

What is the probability of making a Type 1 Error? A. Probability of rejecting the null when it is true B. Probability of accepting the null when it is false C. Probability of rejecting the null when it is false D. Probability of accepting the null when it is true

A. Type I error is detecting an effect that is not present.

If we reduce the error probability of making a Type 1 error, we ______ the probability of making a Type 2 error. A. Increase B. Make no change C. Decrease

A. We increase the probability of making a Type 2 error.

In a pilot study of the effects of living near power stations and the incidence of birth defects, we set our alpha level at 5%, or .05. However for the larger study, we want to be more protective against Type 1 errors. Which should we set as our main alpha level? A. 0.01 B. 0.05 C. 0.10 D. 0

A. We should set our alpha level to .01.

What distribution is commonly known as the "Bell Curve"? A. Bernoulli Trial B. Binomial Distribution C. HypergeometricDistribution D. Normal Distribution

D. Normal distribution is commonly known as the "Bell Curve".

Which three inputs are required to calculate a confidence interval at a given level of confidence? A. Mean, Standard Deviation, and multiplier B. Variance, Standard Error, and multiplier C. Mean, Variance, and Standard Error D. Mean, Standard Error, and multiplie

D. The mean, standard error, and multiplier are required to calculate a confidence interval at a given level of confidence.