Suppose that there are two (2) candidates (i.e., Jones and Johns) in the upcoming presidential election. Sara notes that she has discussed the presidential election candidates with 15 friends, and 10 said that they are voting for candidate Jones. Sara is therefore convinced that candidate Jones will win the election because Jones gets more than 50% of votes.
Answer the following questions in the space provided below:
- Based on what you now know about statistical inference, is Sara’s conclusion a logical conclusion? Why or why not?
- How many friend samples Sara should have in order to draw the conclusion with 95% confidence interval? Why?
- How would you explain your conclusion to Sara without using any statistical jargon? Why?
1) The mean and the variance are equal in«
2) The difference between the sample mean and the population mean is called the«
3) A dummy variable or indicator variable«
4) A Type I error is«
5) Which of the following measures of central location is affected most by extreme values?
6) A correlation matrix«
7) In a set of observations, which measure of central tendency reports the value that occurs most often?
8) Which level of measurement is required for the median?
9) Which level of measurement is required for the mode?
10) The weighted mean is a special case of what?
11) We use the general rule of multiplication to combine«
12) A local trade union consists of plumbers and electricians. Classified according to rank: Apprentice Journeyman Master Total
Plumbers 25 20 30 75
Electricians 15 40 20 75
40 60 50
A member of the union is selected at random. Given that the person selected is anelectrician, what is the probability that the person is a master?
13) Suppose a population consisted of 20 items. How many different samples of n = 3 are possible?
14) In the 1936 Presidential Election Franklin D. Roosevelt defeated Alfred E. Landon in a landslide vote. A Landon victory had been predicted by the Literary Digest, a magazine that ran the oldest, largest, and most widely publicized of the polls at the time. The Digest’s final prediction was based on 10 million sample ballots mailed to prospective voters, and 2.3 million were returned. The sample of voters was drawn from lists of automobile and telephone owners. Despite the massive size of this sample, it failed to predict a Roosevelt victory, being off the mark by 19 percentage points. The Digest was wrong because«
15) A discrete variable«
16) In a study on the effect of reinforcement on learning from a company online training program, two experimental treatments are planned: reinforcement given after every learning module, or reinforcement given after every two learning modules. Reinforcement is accomplished with the addition of more examples. Which one of the following control groups would serve best in this study?
17) Which of the following is a correct statement about a probability?
18) The central limit theorem is important to market researchers because it states that as sample sizes increase, the distribution of the sample ________ collected from consumers on any topic of interest being researched approaches the normal distribution.
19) To find confidence intervals for the mean of a normal distribution, the t distribution is usually used in practical applications instead of the standard normal distribution because«
20) In a two-sample test of means for independent samples, we use the z distribution when«
21) The special rule of addition is used to combine«
22) A sample of 5 companies were examined for changes in their relative market share. The results showed the following increases and decreases: ±5, 10, 10, 5, ±10.
23) A nominal scale variable«
24) Bob is interested in opening a candy store in his town. He believes that his customers will spend an average of $75 or more in annual purchases (the alternative hypothesis). Bob hires a consultant to test this belief. The consultant tested this conjecture on a sample of 100 customers and found the p-value for the test statistic satisfied p > .25, then«
25) The ratio scale of measurement«
26) In the world of market research, the use of a questionnaire often plays a vital role in gaining useful business intelligence because«
27) Which of the following is a requirement for a two-sample test of proportions?
28) The multiple standard error of estimate is«
29) A carefully designed business experiment has just been concluded. Unfortunately, use of alpha = .05 indicated no significant differences among four treatments. What useful information can you supply future investigators when you report on this experiment?
30) We wish to develop a confidence interval for the population mean. The population follows the normal distribution, the standard deviation of the population is 3, and we have a sample of 10 observations. We decide to use the 90% level of confidence. The appropriate value of to represent the level of confidence is.