Statistics Questions

when a sample size is less than 30, what theorem no longer holds?

Without single or double blind there can be

if you increase sample size, margin of error

Empircal rule. w/in 1 standard deviation

Empirical rule w/in 3 standard deviations

Empirical rule w/in 2 standard deviations

what does a small effect size mean between groups?

what is the variability when all the scores within groups are the same within groups?

what is a small, medium, and large effect size? are these measured in absolute value?

what range does effect size fall into?

how do we compare more than 2 means?

so if the between group variance is larger than the within group variance, what can we do we do with our null?

what changes in a z-test if you have a directional hypothesis?

Consider data for four random variables T, U, V, W. For each variable, there are six observations (n = 6). You should do this without computing the skewness coefficient:T = (1, 3, 4, 4, 5, 8)U = (1, 1, 1, 2, 3, 4)V = (1, 2, 3, 3, 4, 5)W = (1, 2, 3, 4, 4, 4)The skewness coefficient for variable U is approximately:

Suppose that a population distribution has a mean and a standard deviation. Now, suppose that you draw an infinite number of random samples from this population with each sample consisting of 4 observations and you compute an infinite number of sample means. The standard deviation of the sample means (the standard error) is ____ as the population standard deviation.

Consider data for four random variables T, U, V, W. For each variable, there are six observations (n = 6):T = (1, 3, 4, 4, 5, 8)U = (1, 1, 1, 2, 3, 4)V = (1, 2, 3, 3, 4, 5)W = (1, 2, 3, 4, 4, 4)Using the methods described in the lecture, the upper quartile for variable T is:

Suppose that in the population, 20 percent of smokers quit each year. There is a small pilot program that provides relaxation exercises, meditation, and other techniques designed to make quitting smoking easier. At the end of one year, 20 of 50 smokers in the treatment group have stopped smoking. The Z-statistic is __________ and you __________ reject the null hypothesis at the 1-percent level of significance.

Suppose that you have data for General Electric stock prices at the closing date of the stock exchange for everyday of the year when the stock market is open. These data are best described as:

Suppose that the mean salary in a large corporation is $80,000 with a standard deviation of $24,000. What is the probability that a randomly selected worker will have a salary less than $68,000?

__________ is the measure of variability most affected by an outlier score.