So false would be your answerA sample of n = 4 scores has a mean of M = 8. If one new score with a value of X = 3 is added to the sample, what will be the value for the new mean?A. M=7.0A normal distribution has a mean of μ = 70 with σ = 12. If one score is randomly selected from this distribution, what is the probability that the score will be greater than X = 58?A. 0.8413On an exam with μ = 52, you have a score of X = 56. Which of the following values for the standard deviation would give you the highest position in the class distribution?σ = 2Under what circumstances is a score that is 15 points above the mean an extreme score relatively far from the mean?When the population standard deviation is much smaller than 15For a sample of n = 16 scores, how many scores are used to calculate the sample variance?D. 16A normal distribution has a mean of μ = 80 with σ = 20. What score separates the lowest 30% of the distribution from the rest of the scores?B. X=69.6A normal distribution has a mean of μ = 100 with σ = 20. If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 80 and X = 100?B. 0.1587If sample variance is computed by dividing SS by df = n - 1, then the average value of the sample variances from all the possible random samples will be the population variance.C. exactly equal toA population of N = 6 scores has ΣX = 12 and ΣX2 = 54. What is the value of SS for this population?C. 30One sample has n = 4 scores and M = 10. A second sample has n = 6 scores and M = 5. If the two samples are combined, then what is the weighted mean for the combined sample?C. 70/10 = 7.0A jar contains 10 red marbles and 30 blue marbles. What is the probability of randomly selecting a red marble from the jar?B. 10/40After every score in a sample is multiplied by 3, the mean is calculated and found to be M = 21. What was the mean for the original scores?A. 7John drives to work each morning and the trip takes an average of μ = 38 minutes. The distribution of driving times is approximately normal with a standard deviation of σ = 5 minutes. For a randomly selected morning, what is the probability that John's drive to work will take less than 35 minutes?D. 0.2743Scores on the SAT form a normal distribution with a mean of μ = 500 with σ = 100. If the state college only accepts students who score in the top 60% on the SAT, what is the minimum score needed to be accepted?A. X=475Which of the following symbols identifies the population standard deviation?C. σA sample of n = 100 scores is selected from a population with μ = 80 with σ = 20. On average, how much error is expected between the sample mean and the population mean?C. 2 pointsWhat happens to the standard error of M as sample size increases?B. it decreasesIf all the possible random samples with n = 36 scores are selected from a normal population with μ = 80 and σ = 18, and the mean is calculated for each sample, then what is the average of all the sample means?C. 80A sample of n = 4 scores has a standard error of 10 points. For the same population, what is the standard error for a sample of n = 16 scores?C. 5A population has μ = 50. What value of σ would make X = 55 a more central, representative score in the population?D. σ = 20A researcher measures eye color for a sample of n = 50 people. Which measure of central tendency would be appropriate to summarize the measurements?C. modeA distribution is positively skewed. Which is the most probable order, from smallest to largest, for the three measures of central tendency?B. mode, median, meanFor the population of scores shown in the frequency distribution table, the mean is .
X f
5 2
4 1
3 3
2 2
1 2D. 29/10 = 2.90Samples of size n = 9 are selected from a population with μ = 80 with σ = 18. What is the standard error for the distribution of sample means?C. 6For a particular population, a sample of n = 9 scores has a standard error of 8. For the same population, a sample of n = 16 scores would have a standard error of .B. 6For a sample with M = 80, a score of X = 88 corresponds to z = 2.00. What is the sample standard deviation?B. 4You have a score of X = 65 on a math exam. The mean score for the class on the exam is μ = 70. Which of the following values for the standard deviation would give you the most favorable position within the class?D. σ = 10A true/false test has 100 questions. Using the normal approximation to the binomial distribution, what is the probability of getting more than 55 correct by just guessing?B. p(X > 55.5)What term is used to describe the shape of a distribution in which the scores pile up on the left-hand side of the graph and taper off to the right?B. positively skewedFor a population with μ = 80 and σ = 10, what is the X value corresponding to z = -0.50?C. 75What is the value of SS (sum of squared deviations) for the following population?
Population: 2, 3, 0, 5A. 13
