(H) FALSE Which of the following statisties describes the spread of the normal distribution? (a) mean...
[2] 11. Y is a value which is drawn from a normal distribution with mean 2.5 and standard deviation 2.5. The probability that y is positive is: A. 0.1587 B. 0.5 C. 0.6587 D. 0.8413 E. none of the above
Assuming normal speed distribution, if d is defined as +2 km/h, standard deviation is as 5km/h, and the mean speed needs to be determined (1.e. 85th percentile speed, ) at a significance level of 0.05, determine the minimum sample size required. Select one: O a. 37 O b. 72 O c. None O d. 30
Which of the following statements is correct? a. A normal distribution is uniquely defined by its mean µ and standard deviation sigma. b. The highest point on a normal curve is at the mean. c. In a normal distribution the mean is also the mode. d. All of the above.
QUESTION 23 Which of the following is the most descriptive measure of spread? Median Standard deviation Range Mean QUESTION 24 Which of the following describes a measure of Spread? Range and interquartile range (IQR) Variance and Standard Deviation (std) Mean, Median and Mode More than one answer is correct QUESTION 25 Sample standard deviation s is the estimator of population standard deviation o. True False
61. The figure above shows the standard normal distribution, with mean 0 and standard deviation 1, including approximate percents of the distribution corresponding to the six regions shown. The random variable Y is normally distributed with a mean of 470, and the value Y = 340 is at the 15th percentile of the distribution. Of the following, which is the best estimate of the standard deviation of the distribution? A. 125 B. 135 C. 145 D. 155 E. 165
In a normal distribution with a mean of 90 and a standard deviation of 10, which of the following scores lie within +/- one standard deviation from the mean? Select one: a. 10 - 100. b. 10 - 90. c. 80 - 100. d. 70 -110.
QUESTION 5 Which statement concerning the t-distribution is false? O AT follows a standard normal distribution OB. The smaller the degrees of freedom the flatter the curve. OC. The t-distribution has a larger standard deviation than the Standard Normal Curve. OD. T-distributions have a mean of 0. o E. The total area under the density curve depends on the degrees of freedom. QUESTION 6 The t-procedures are robust when A. sample size is 12 and the sample data is not...
Which of the following statements is not a property of the normal probability distribution?A. The normal distribution is symmetricB. Exactly two-thirds of all possible observed values of the random variable x are within plus or minus one standard deviations of the population meanC. The mean, median and mode are equalD. The area under the normal curve to the right of the mean is equal to the area under the normal curve to the left of the meanE. All of the...
The distribution of the population of the millions of household incomes in California is skewed to the right. Which of the following best describes what happens to the sampling distribution of the sample mean when the size of a random sample increases from 10 to 100? explain why. ) Its mean gets closer to the population mean, its standard deviation gets closer to the population standard deviation, and its shape gets closer to the population’s shape. b) Its mean gets...
Question 5 In a normal distribution, if l take the mean value and I add or subtract 1.96 times the standard error of the mean SEM), I would obtain 99.7% of my sample a. True b. False c. We don't have enough information d. None of the above