BMGT6022 Probability Distributions

Which of the following characteristics do all normal distributions have (in theory)?

• symmetrical

• area under the curve adds to 1

• mean of 0 and standard deviation of 1

• mean = median = mode

Which function in Excel is used to calculate the probability less than (or no more than) a particular value in a Normal distribution? Example: what is the probability of a bottle of water being less than 497mL?

• =NORM.INV()

• =NORM.DIST()

• =1-NORM.DIST()

• =PROB()

Which function in Excel is used to calculate the probability more than (or no less than) a particular value in a Normal distribution? Example: what is the probability of a bottle of water being more than 503mL?

• =NORM.INV()

• =NORM.DIST()

• =1-NORM.DIST()

• =PROB()

Which function in Excel is used to calculate the probability between two values of a Normal distribution? Example: what is the probability of a bottle of water being between 497 and 503mL?

• =NORM.INV()

• =NORM.DIST()

• =NORM.DIST() - NORM.DIST()

• =PROB()

Which function in Excel is used to calculate the value for which a specified proportion of the Normal curve is below? Example: 25% of bottles contain less than what volume?

• =NORM.INV()

• =NORM.DIST()

• =NORM.DIST() - NORM.DIST()

• =PROB()

If 39% of adult males measure at least 1.8m, then what proportion of adult males are less than 1.8m tall?

• 39%

• 50%

• 61%

• 82%

In a production run of 500 widgets, how many are likely to weigh less than 30g if the mean weight is 40g and the standard deviation is 2g. To calculate this in Excel:

• =NORM.DIST(30,40,2,FALSE)

• =NORM.DIST(30,40,2,TRUE)*500

• =NORM.DIST(30,40,2,FALSE)*500

• =NORM.INV(30,40,2,TRUE)

A theoretical distribution that describes where a particular sample estimate comes from is a:

• sampling distribution

• Normal distribution

• supply chain distribution

• weight distribution

If we generated thousands of random samples of a certain size over and over, and plotted the sample means on a histogram, we would have:

• the Normal distribution

• the Binomial distribution

• the Probability distribution

• the Student T distribution

Which of the following is true about the Student T distribution?

• The greater the sample size, the more Normal it becomes

• It is a sampling distribution of proportions

• It is an unbiased estimator of the true population mean

• The smaller the sample size, the flatter and more spread out it becomes