Download Fundamentals of Statistics: Measurement Levels, Distributions, and Hypothesis Testing and more Exams Descriptive statistics in PDF only on Docsity!
BESC 3010 FINAL WITH COMPLETE
SOLUTIONS.
In a sample of women, the number of children that each woman has is an example of which level of measurement? --Answer-- Ratio Military ranks are an example of what level of measurement? --Answer-- Ordinal Gender is an example of what level of measurement? --Answer-- Nominal Which label would be most appropriate for describing the distribution below? 1 11 111 111111 --Answer-- Positively Skewed Which label would be most appropriate for describing the distribution below? 1 11111 1111111 111111111 11111111111 --Answer-- Normal Which label would be most appropriate for describing the distribution below? (A normal curve has been superimposed on the distribution for comparison.) --Answer-- Mesokurtic In which of the following situations is the median an appropriate measure of central tendency? --Answer-- The researcher has ordinal data Which of the following is NOT true about the abnormal distribution? -- Answer-- Kurtosis = 1
The visual difference between bar graphs and histograms is that in __________ the bars touch each other and in __________ the bars do not touch. --Answer-- Histograms, bar graphs Compared to the normal distribution, a leptokurtic distribution has a ___________ than the normal distribution. --Answer-- Taller peak If the dots on a scatterplot generally extend from the bottom left to the upper right of the diagram but are very widely spread out, the researcher would report the correlation as: --Answer-- Weak and positive The three measures of variability are: --Answer-- Range, variance, standard deviation Which option is the mean of the numbers below? 4 5 4 4 3 5 6 3 4 2 --Answer-- 4 Which option is the median of the numbers below? 4 5 4 4 3 5 6 3 4 2 --Answer-- 4 Which option is the mode of the numbers below? 4 5 4 4 3 5 6 3 4 2 --Answer-- 4 What is the standard deviation of the sample represented by the numbers below? 4 5 4 4 3 5 6 3 4 2 (Note that if you compare this question to the paper version of the practice final or the video reviews, one of the answers is slightly different. The correct one is listed here.) --Answer-- 1. What is the variance of the sample represented by the numbers below? 4 5 4 4 3 5 6 3 4 2
In a normal distribution, it is very unusual to find scores outside of what range of z-scores? --Answer-- -3 and 3 If a raw score distribution has a mean of 12 and a standard deviation of 3, what number would have a z-score of -2? --Answer-- 6 A researcher uses alpha as the criteria or critical value for the maximum probability of incorrectly rejecting the null hypothesis. She conducts a z-test with alpha = .05 and finds the p-value is .02. The researcher should: -- Answer-- Reject the null hypothesis Which of the following is MOST sensitive to extreme scores? --Answer-- Range Most data sets in social science studies are from ________. --Answer-- Samples A sampling distribution of means is: --Answer-- A distribution of means from many samples The sample mean is a(n) ________ of the population mean. --Answer-- Unbiased point estimate According to the Central Limit Theorem, it is safe to assume that given an infinite number of samples: --Answer-- The shape of the distribution of sample means will approximate a normal curve if the sample size (n) used to calculate each mean > 30. In hypothesis testing, if the null hypothesis has been rejected, what hypothesis do we assume? --Answer-- The alternative hypothesis In null hypothesis testing, if the critical value is less extreme than the observed value (i.e., test value), then: --Answer-- The null hypothesis is retained (i.e., not rejected) Which of the following is always true for "statistically significant" results? -- Answer-- None of the above
Which of the following statements below is inappropriate when discussing results of statistical significance tests? --Answer-- The null hypothesis has been proven true What would be the advantage of increasing N in null hypothesis significance testing? --Answer-- The null hypothesis would be more likely to be rejected p-values are: --Answer-- Influenced by sample size Which of the following is an impossible value for both p and alpha? -- Answer--. If we use alpha as the criteria or critical value for the maximum probability of incorrectly rejecting the null hypothesis, then when the p-value is less than alpha: --Answer-- The null hypothesis is rejected A researcher conducts two studies on relational satisfaction with the same independent and dependent variables. After conducting a two-sample t-test, Study A was found to have an effect size of .65 and a p-value of .0001. Study B was found to have an effect size of .65 and a p-value of .076. Which study has the smaller sample size? --Answer-- Study B A researcher conducts two studies on depression severity with the same independent and dependent variables. Study A had a sample size of 500 and the p-value was calculated at .002. Study B also had a sample size of 500 and the p-value was calculated at .033. Which study had the smaller effect size? --Answer-- Study B The effect size is calculated as d = .89. What does this mean? --Answer-- The sample mean is .89 standard deviations away from the population mean If Cohen's d = 2.25, then which of the following is always true? --Answer-- There are 2.25 standard deviations between the two sample means If Cohen's d is very small, the two means are ______ each other --Answer-- close to Committing a Type II error is defined as: --Answer-- Not rejecting (i.e., Retaining) the null hypothesis when it should have been rejected
The difference between a predicted Y score and an actual observed Y score is known as the --Answer-- residual Which of the following is true about regression towards the mean? -- Answer-- Predicted Y values will not always ben perfect unless r = +- 1 Which of the following is an impossible value for r2? --Answer-- 1. Correlations may not be interpretable for which type of relationship? -- Answer-- Nonlinear Which of the following illustrates a negative correlation? --Answer-- The more often a person visits the dentist, the fewer cavities they ahve A researcher calculated a Pearson's r found that there was no relationship between X and Y. The effect size for the data is --Answer-- 0 When Pearson's r is negative, variables are said to have an "inverse relationship". What does this mean? --Answer-- That when X increases, Y decreases The closer Pearson's r correlations are to -1 or 1, the __________ the relationship between X and Y is. --Answer-- Stronger A data set has non-linear relationship between two variables. Which of the calculations below are affected by this problem? --Answer-- Pearson's r Which statistic is defined as the proportion variance accounted in the dependent variable by the independent variable? --Answer-- r What is the minimum level of measurement to calculate a Pearson's r correlation coefficient? --Answer-- Interval If r = .65, then the members in a sample who have _________ values on the independent variable have ______ values on the dependent variable. -- Answer-- Lower, lower For the five data points in the scatterplot below, the correlation is r = .95, as shown with the regression line. Why is Pearson's r a problematic statistic to
summarize the relationship for these data? --Answer-- The outlier distorts the relationship between X and Y.
