AK2_230 - ECO 230 Economic Statistics Answer Key to...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
ECO 230 Marianna Kudlyak Economic Statistics Spring 2007 Answer Key to Homework #2 Total points: 10. Graded exercises: Ex.1 (2 points), Ex.4 (2 points), Ex. 6 (2 points), and Ex. 7 (2 points). 0.5 points were added for the presence of each of the remaining 4 exercises. Exercise 1. A survey of 12 students at a local university asked approximately how many hours per week they spend on the Internet. Their answers are listed below. 1 3 0 5 8 2 2730 1 51 2 1 3 1 6 a) What are the mean and median for this data? Using the formula for sample mean: mean is 9.5 To obtain a median, order the data in ascending order: 0 0 3 5 7 8 12 13 13 15 16 22 Median is 8+(1/2)*(12-8) = 8+2=10 b) From the data presented above, calculate the first and third quartiles. 1 st quartile: (1/4)*(n+1)th observation = 3.25th observation = 3+(1/4)*(5-3) = 3+2/4=3.5 3 rd quartile: (3/4)*(n+1)th observation = 9.75th observation = 13+(3/4)*(15-13) = 13+(6/4) = 14.5 c) From the data presented above calculate the inter-quartile range. 3 rd quartile - 1 st quartile = 14.5-3.5 = 11 d) What is the coefficient of variation for this data? Using the value of the standard deviation from part e) below, CV = = x s 6.82/9.5 = 0.72 or 72% e) What is the variance and the standard deviation for this data? Using the formulas for sample standard deviation and sample variance: s 2 = = = 1 12 ) ( 12 1 2 i i x x 46.45 s = 6.82 f) What is the range of this data? Range is Max – Min = 22-0=22 Exercise 2. Inflation rates in small country for the past five years have been 10%, 7%, 13%, 9%, and 12%. a) What is the average annual rate of inflation? Use the geometric mean to calculate the mean inflation rates: {(10)(7)(13)(9)(12)] 1/5 = 9.96536 b) If this rate of inflation continues, how long will it take for prices to double?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Number of years for the inflation to double at this growth rate: Solve the following equation for x: (1.0996536) X = 2.0. Take the log of both sides of the equation: X log(1.0996536) = log (2.0). Simplify: X = .301029996/.0412559 = 7.297 years Exercise 3. Newbold, Carlson and Thorne, Problem 3.31 p.64.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/09/2008 for the course ECO 230 taught by Professor Kudlyak during the Spring '08 term at Rochester.

Page1 / 6

AK2_230 - ECO 230 Economic Statistics Answer Key to...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online