Density curves The following figure is a density curve that models a distribution of quantitative data. Trace the curve onto your paper.

a. What percent of observations have values less than 13? Justify your answer.

b. Mark the approximate location of the median. Explain your choice of location.

c. Mark the approximate location of the mean. Explain your choice of location.

Short Answer

Expert verified

Part (a) The 92percent of observations have values less than 13

Part (b) The mean's approximate location is 7

Part (c) The mean's approximate location is 10

Step by step solution

01

Part (a) Step 1: Given information

As per the given graph,

P (X > 13) = 0.08

02

Part (a) Step 2: Calculation

The fraction of observations with values less than 13 can be determined using the formula:

P(X<13)=1P(X13)=10.08=0.92

Thus, the required answer is 0.92

03

Part (b) Step 1: Explanation

Because the graph is slanted to the right. It signifies that the mode is higher than the median, and the median is higher than the mean. The distribution ranges from 0to 20Consider that the median is less than ten times the mean, implying that the median is less than ten times the mean. As a result, the median's approximate location is 7

04

Part (c) Step 1: Explanation

Because the graph is slanted to the right. It signifies that the mode is higher than the median, and the median is higher than the mean. The distribution ranges from 0to 20As a result, the average is around ten.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

The weights of laboratory cockroaches can be modeled with a Normal distribution having a mean of 80 grams and a standard deviation of 2 grams. The following figure is the Normal curve for this distribution of weights.

Point C on this Normal curve corresponds to

a. 84 grams.

b. 82 grams.

c. 78 grams.

d. 76 grams.

e. 74 grams.

Taxi! In 2016, taxicabs in Los Angeles charged an initial fee of \(2.85 plus \)2.70 per mile. In equation form, Fare=2.85+2.7(miles). At the end of a

month, a businessman collects all his taxicab receipts and calculates some numerical

summaries. The mean fare he paid was \(15.45with a standard deviation of \)10.20What are the mean and standard deviation of the lengths of his cab rides in miles?

At some fast-food restaurants, customers who want a lid for their drinks get them from a large stack near the straws, napkins, and condiments. The lids are made with a small amount of flexibility so they can be stretched across the mouth of the cup and then snugly secured. When lids are too small or too large, customers can get very frustrated, especially if they end up spilling their drinks. At one particular restaurant, large drink cups require lids with a “diameter” of between 3.95 and 4.05 inches. The restaurant’s lid supplier claims that the diameter of its large lids follows a Normal distribution with a mean of 3.98 inches and a standard deviation of 0.02 inches. Assume that the supplier’s claim is true.

Put a lid on it! The supplier is considering two changes to reduce to 1% the percentage of its large-cup lids that are too small. One strategy is to adjust the mean diameter of its lids. Another option is to alter the production process, thereby decreasing the standard deviation of the lid diameters.

a. If the standard deviation remains at σ=0.02 inch, at what value should the

supplier set the mean diameter of its large-cup lids so that only 1% is too small to fit?

b. If the mean diameter stays at μ=3.98 inches, what value of the standard

deviation will result in only 1% of lids that are too small to fit?

c. Which of the two options in parts (a) and (b) do you think is preferable? Justify your answer. (Be sure to consider the effect of these changes on the percent of lids that are too large to fit.)σ=0.02

Deciles The deciles of any distribution are the points that mark off the lowest 10%and the highest 10%. The deciles of a density curve are therefore the points with area 0.1and 0.9to their left under the curve.

(a) What are the deciles of the standard Normal distribution?

(b) The heights of young women are approximately Normal with mean 64.5inches and standard deviation 2.5inches. What are the deciles of this distribution? Show your work

Multiple choice: Select the best answer. Mark receives a score report detailing his performance on a statewide test. On the math section, Mark earned a raw score of 39, which placed him at the 68th percentile. This means that

(a) Mark did better than about 39% of the students who took the test.

(b) Mark did worse than about 39% of the students who took the test.

(c) Mark did better than about 68%of the students who took the test.

(d) Mark did worse than about 68% of the students who took the test.

(e) Mark got fewer than half of the questions correct on this test.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free