Mod. 20.2 Day 2 Lesson - C.I and Probability

Multiple Choice

What is the purpose of the Normal Cumulative Distribution Function (CDF) in statistics?

• To calculate the probability that a random variable is less than or equal to a certain value in a normal distribution

• To calculate the mean of a dataset

• To find the mode of a distribution

• To determine the median of a dataset

Add to Test Sheet

Fill in the Blanks

Fill in the blank: The formula for the z-score for a sample mean is z = (x -

)/SE.

Multiple Choice

The weights of baby giraffes are known to have a mean of 125 pounds and a standard deviation of 15 pounds. If we obtained a random sample of 40 baby giraffes:

What is the probability that the sample mean is more than 119 pounds?

• 99.43%

• 0.89%

• 95.2%

• 2.37

Multiple Choice

What is the standard error of the proportion for the company's claim that 90% of orders are shipped within 24 hours, given a sample size of 100 orders?

• 0.03

• 0.09

• 0.01

• 0.9

Math Response

An online retail company prides itself on its fast shipping. They claim that 90% of orders are shipped within 24 hours. To monitor this, they take a random sample of customer orders each week.

Data:

The company's claim: 90% of orders are shipped within 24 hours.

Sample size: n = 100 orders

What is the probability that the sample proportion will be between 88% and 92%?

Type answer here

Correct Answer: 49.71

Deg^°

Rad

Multiple Choice

Which steps are involved in finding the probability that a sample mean falls within a certain range using the normalcdf function on a calculator?

• Find the standard error, calculate z-scores, use normalcdf with z-scores as limits

• Find the median, calculate the mean, use normalcdf with mean as limit

• Calculate the variance, use invNorm, then use normalcdf

• Find the mode, use tpdf, then use normalcdf

Multiple Choice

How confident do you feel about calculating probabilities using the normal cumulative distribution function (CDF) and technology after today's lesson?

• Very confident

• Somewhat confident

• Not very confident

• Not at all confident

Open Ended

What is one question you still have about using the normal cumulative distribution function (CDF) to calculate probabilities?