BUAL 2650 EXAM 1 STUDY GUIDE QUESTIONS AND ANSWERS WITH 100% ACCURATE RATED A+.

normal probability plot - correct answer graphic used to virtually check whether data comes from a normal population relative frequencies of all possible values of x are about the same - correct answer its appropriate to use the uniform distribution to describe a continuous random variable x when: np = 5 and n(1-p) = 5 - correct answer normal approximation of the binomial distribution is appropriate when: the fill weight is less than 910 grams - correct answer the fill weight of a certain cereal is normally distributed with a mean of 910 grams and a standard deviation of 5 grams. we calculated the value of z for a specific box of this brand of cereal, and the z value was negative. this negative z value indicates that: 95.44% of all possible observed values of the random variable x are plus or minus 3 standard deviations of the population mean - correct answer which statement is NOT a property of the normal probability distribution? 99.73 - correct answer if the random variable x is normally distributed, ______ % of all possible observed values of x will be within 3 standard deviations of the mean standard deviations - correct answer the z value tells us the number of ______ that a value of x is from the mean uniform distribution - correct answer continuous probability distribution having a rectangular shape, where the probability is evenly distributed over an interval or numbers mean, standard deviation - correct answer specific shape of each normal distribution is determined by its _________ & ____________. equal 1 - correct answer area under the curve of a valid continuous probability distribution must ________. larger values - correct answer what values of the standard deviation result in a normal curve that is wider & flatter? 0 - correct answer the mean of a standard normal distribution is always equal to __________ .1587 - correct answer given that the length an athlete throws a hammer is a normal random variable with mean 50 feet and standard deviation 5 feet, what is the probability he throws it NO LESS than 55 feet? .5662 - correct answer if x is a binomial random variable where n=100 & p=.1, find the probability that x = 10, using the normal approximation to the binomial .3814 - correct answer what's the probability that a standard normal random variable will be between .3 & 3.2? increases, normal - correct answer for non-normal populations, as the sample size (n) ___________ , the distribution of sample means approaches a(n) ___________ distribution the central limit theorem - correct answer __________ says that if the sample size is sufficiently large, then the sample means are approximately normally distributed .1056 - correct answer Find P(x ̄x ̄ 35) if μ = 40, σx = 16, n = 16. .0668 - correct answer packages for sugar bags for sweeter sugar inc. have an average weight of 16 ounces and a SD of .2 ounces. the weights of the sugar packages are normally distributed. what is the probability that 16 ounces randomly selected packages will have a weight in excess of 16.075 ounces? .8413 - correct answer Find P(x ̄x ̄ 172), if μ = 175 and σ2xσx2 = 9. number of degrees of freedom - correct answer the exact spread of the t distribution depends on the ___________. t distribution - correct answer when the population is normally distributed, population standard deviation is unknown, and the sample size is n=15, the confidence interval for the population mean is based on ________? decreases - correct answer as standard deviation decreases, the width of the confidence interval ________ sample mean - correct answer a confidence interval for the population mean is an interval constructed around the __________ 2.8140 to 3.1860 - correct answer in a manufacturing process, a random sample of 9 manufactured bolts has a mean length of 3 inches with a variance of .09 and is normally distributed. what is the 90% confidence interval for the true mean length of the manufactured bolt? 2.864 to 3.136 - correct answer in a manufacturing process, a random sample of 36 manufactured bolts has a mean length of 3 inches with a standard deviation of .3 inches. what is the 99% confidence interval for the true mean length of the manufactured bolt? 601 - correct answer in a manufacturing process, we wanna measure the average length of a certain type of bolt. past data indicates that standard deviation = .25 inches. how many manufactured bolts should be sampled in order to make us 95% confident that the sample mean bolt length is within .02 inches of the true mean bolt length? type 1 - correct answer what error is rejecting a true null hypothesis? p = .66 - correct answer a recent study conducted by the by the state govt attempts to determine whether the voting public supports a further increase in cigarette taxes. the opinion poll recently sampled 1,500 voting age citizens. 1,020 of the sampled citizens were in favor of an increase in cigarette taxes. the state govt wants to decide if there's enough evidence to establish whether the proportion of citizens supporting an increase in cigarette taxes is significantly greater than .66. identify the null hypothesis