1 / 7

R's Normal Distribution Alphabet

R's Normal Distribution Alphabet. Where we're headed. In the last lab, you were able to overlay a normal curve on histograms of data to help you decide if the data's distribution is close to a normal distribution.

ndenis
Download Presentation

R's Normal Distribution Alphabet

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. R's Normal Distribution Alphabet

  2. Where we're headed • In the last lab, you were able to overlay a normal curve on histograms of data to help you decide if the data's distribution is close to a normal distribution. • In this lab, we'll learn how to use some other R functions to calculate percentages of normal distributions.

  3. Using the normal model The distribution of female heights is Normally distributed with a mean of 64.2 inches and standard deviation of 2.9 inches. In order to find my percentile in this distribution, I had to calculate my z-score and use the table for the standard Normal curve. To have Rstudio calculate percentiles, use the following code: pnorm(____, mean = , sd = ____) Calculate my percentile. My height is 67 inches.

  4. P's and Q's • We've seen that we can use pnorm to calculate percentiles based on a specified quantity. Hence, why we call it “P” norm. • Now we'll see how to do the opposite. That is, calculate a quantity for a specific percentile. Hence why we'll call this a “Q” norm.

  5. Q’s Use the code: qnorm(____, mean = ____, sd = ____) to find the height of a female who is taller than 30% of all females?

  6. Ketchup • A fast food restaurant has just installed a new automatic ketchup dispenser for use in preparing its burgers. The amount of ketchup dispensed by the machine follows a Normal distribution with mean 1.05 ounces and standard deviation 0.08 ounces.

  7. Putting it all together • Create a Normal density curve that models this data. • At what percentile is a quantity of 1 ounce of ketchup? • How much ketchup was dispensed if it was at the 20th percentile in the distribution? • If the restaurant’s goal is to put between 1 and 1.2 ounces of ketchup on each burger, what percent of the time will this happen?

More Related