EBook Problems EDA IntroVar

EBook Problems Set - The Nature of Data and Variation Problems

Problem 1

Researchers do a study on the number of cars that a person owns. They think that the distribution of their data might be normal, even though the median is much smaller than the mean. They make a p-plot. What does it look like?

• Choose one answer.

(a) It's not a straight line.

(b) It's a bell curve.

(c) It's a group of points clustered around the middle of the plot.

(d) It's a straight line.

Answer

 (a)

Problem 2

Bicycles arrive at a bike shop in boxes. Before they can be sold, they must be unpacked, assembled, and tuned (lubricated, adjusted,etc). Based on past experience, the shop manager makes the following assumptions about how long this may take: The times for each setup phase are independent The times for each phase follow a Normal curve The means and standard deviations of the times (in minutes) are as shown

Phase	Mean	SD
Unpacking	3.5	0.7
Assembly	21.8	2.4
Tuning	21.8	2.7

What are the mean and standard deviation for the total bicycle set up time?

• Choose one answer.

(a) Mean = 100 min, standard deviation = 12 min

(b) Can't be determined with the information given

(c) Mean = 37.6 min, standard deviation = 3.7 min

(d) Mean = 20 min, standard deviation = 13.69 min

Answer

 (c)

Problem 3

Let X be a random variable with mean 80 and standard deviation 12. Find the mean and the variance of the following variable: 2X-100

• Choose one answer.

(a) Mean = 100, variance = 288

(b) Mean = 60, variance = 12

(c) Mean = 160, variance = 144

(d) Mean = 60, variance = 576

Answer

 (d)

Problem 4

Let X be a random variable with mean 80 and standard deviation 12. Find the mean and the standard deviation of the following variable: X- 20

• Choose one answer.

(a) Mean = 60, standard deviation = 144

(b) Mean = 60, standard deviation = 12

(c) Mean = 80, standard deviation = 12

(d) Mean = 60, standard deviation = -8

Answer

 (b)

---

• Back to Ebook
• SOCR Home page: http://www.socr.ucla.edu

---

---

Translate this page:

(default)	Deutsch	Español	Français	Italiano	Português	日本語	България	الامارات العربية المتحدة	Suomi	इस भाषा में	Norge
한국어	中文	繁体中文	Русский	Nederlands	Ελληνικά	Hrvatska	Česká republika	Danmark	Polska	România	Sverige