BANA 2372 Business Analysis/Statistics - Exam 2 Practice Questions with Correct Answers

BANA 2372 Business Analysis/Statistics - Exam 2 Practice Questions with Correct Answers ___ of values of a normal random variable are within +/- 1 standard deviation of the mean. - 68.26% ___ of values of a normal random variable are within +/- 2 standard deviation of the mean. - 95.44% ___ of values of a normal random variable are within +/- 3 standard deviation of the mean. - 99.72% ___ is referred to as the rectangular distribution. - Uniform distribution ___is a continuous probability distribution and explains the probability distribution of the time between random occurrences. - Exponential probability distribution 1 /10 10 x f x e , where x 0 The mean of x is ____. The probability that x is less than 5 is ____. - 10; 0.0606 23% of executives believe an employer has no right to read employee's email. With a sample size of 1200 construct a 90% confidence interval for the proportion. Does this sample satisfy the necessary conditions such that the distribution of sample proportions is approximately normal? - yes A college entrance exam scores the following normal distribution with a mean of 540 and a standard deviation of 60. About 68% of students taking the exam will score within what range? - 480 to 600 Page 2/63 ©EmilyCharlene 2024. All Rights Reserved. A continuous probability distribution that is useful in describing the time, or space, between occurrences of an event is a(n) - exponential probability distribution A continuous random variable can assume any value in an interval on the real line or in a collection of intervals. - True A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is _____. - 1/(b − a) A continuous random variable may assume _____. - all values in an interval or collection of intervals A continuous uniform random variable x has a lower bound of a = -3, an upper bound of b = 5. What is p(x -1)? - 0.7500 A continuous uniform random variable x has a lower bound of a = -21, an upper bound of b = -6. What value of x provides an area in the upper tail equal to 0.20? - -9 A health conscious student faithfully wears a device that tracks his steps. Suppose that the number of steps he takes is normally distributed with a mean of 10,000 and a standard deviation of 1500 steps. How many steps would he have to take to make the cut for the top 5% for his distribution? - 12,467 A health conscious student faithfully wears a device that tracks his steps. Suppose that the number of steps he takes is normally distributed with a mean of 10,000 and a standard deviation of 1500 steps. One day he took 15,000 steps. What was his percentage of steps that day? - 99.96% A health conscious student faithfully wears a device that tracks his steps. Suppose that the number of steps he takes is normally distributed with a mean of 10,000 and a standard deviation of 1500 steps. What percent of the time will he exceed 13,000 steps? - 2.28% A mean of 0 and a standard deviation of 1 - minus infinity to infinity Page 3/63 ©EmilyCharlene 2024. All Rights Reserved. A negative value of Z indicates that - the number of standard deviations of an observation is to the left of the mean A negative value of z indicates that: - the number of standard deviations of an observation is below the mean. A normal distribution with a mean of 0 and a standard deviation of 1 is called - a standard normal distribution A normal distribution with a mean of zero and a standard deviation of one is called: - a standard normal probability distribution. A normal probability distribution _____. - is a continuous probability distribution A normal probability distribution is____, and its skewness measure is___. - symmetric; zero A numerical measure from a population, such as a population mean, is called _____. - a parameter A professor at a local university noted that the exam grades of her students were normally distributed with a mean of 73 and a standard deviation of 11. The professor has informed us that 7.93 percent of her students received grades of A. What is the minimum score needed to receive a grade of A? Students who made 57.93 or lower on the exam failed the course. What percent of students failed the course? If 69.5 percent of the students received grades of C or better, what is the minimum score of those who received C's? - 88.51 8.53% Page 4/63 ©EmilyCharlene 2024. All Rights Reserved. 67.39 A property of the exponential distribution is that the ___ and___ are equal. - mean, standard deviation A random sample of 144 observations has a mean of 20, a median of 21, and a mode of 22. The population standard deviation is known to equal 4.8. The 95.44% confidence interval for the population mean is - 19.2 to 20.8 A random variable having a normal distribution with a mean of 0 and a standard deviation of 1. - standard normal probability distribution A random variable is ____ whenever the probability is proportional to the interval's length. - uniformly distributed A sample statistic, such as a sample mean, that estimated the value of the corresponding population parameter is known as a _____________. - point estimator A standard normal distribution is a normal distribution with - any mean and any standard deviation A standard normal distribution is a normal distribution with ____. - a mean of 0 and a standard deviation of 1 A uniform probability distribution is a continuous probability distribution where the probability that the random variable assumes a value in any interval of equal length is ___. - the same for each interval A value of 0.5 that is added and/or subtracted from a value of x when the continuous normal distribution is used to approximate the discrete binomial distribution is called - continuity correction factor About 95.4% of the values of a normal random variable are within approximately how many standard deviations of its mean? - ±2 Page 5/63 ©EmilyCharlene 2024. All Rights Reserved. An experiment consists of three steps. There are four possible results on the first step, three possible results on the second step, and two possible results on the third step. The total number of experimental outcomes is - 24 4 X 3 X 2 = 24 An exponential probability function with an expected population value of two will have a density function of: - f(x)=1/2e^-x/2 Any normal probability distribution can be converted to a standard normal probability distribution through the use of z-scores. - True Approximately ____________ of the values of a random variable in a normally distributed population lie within ±σ standard deviation from the mean. - 68% As the degrees of freedom increase, the t distribution approaches the _____ distribution. - normal Assume that our sample data of height in inches data represents the population of students at UMD and that this population is approximately normal with a mean = 70 inches and standard deviation = 3.5 inches. Let x = height in inches (a continuous, normally distributed random variable) What is P(x 74), ie. probability that x les s than 74? What is P(x 74), ie. probability that x is bigger or equal to 74? What is P(x = 74), ie. probability that x equals to 74? What is P(x 63), i.e.. probability that x is bigger than 63? What is P(63 x 74)? What height is there a 2.5% chance that a randomly drawn student would be shorter than that height? - 0.8729 Page 6/63 ©EmilyCharlene 2024. All Rights Reserved. 0.1271 0 0.9772 0.8501 63.14 Assume that z is a standard normal random variable. Then P(-1.5 (or equal to) z (or equal to) 1.09 equals______. - .7953 Assume z is a standard normal random variable. P(-1.50 z 1.90) equals - 0.0381 Assume z is a standard normal random variable. P(-2.0 z -1.0) equals - 0.1359 Assume z is a standard normal random variable. Then P(-1.5 ≤ z ≤ 1.09) equals _____. - .7953 Assume z is a standard normal random variable. Then P(-1.20 ≤ z ≤ 1.50) equals _____. - .8181 Assume z is a standard normal random variable. Then P(-1.96 ≤ z ≤ -1.4) equals _____. - .0558 Assume z is a standard normal random variable. Then P(1.05 ≤ z ≤ 2.13) equals _____. - none of the answers are correct -.8365 -.4834 - .1303 Assume z is a standard normal random variable. Then P(1.20 ≤ z ≤ 1.85) equals _____. - .08