Exam 1 Answers - z 2 = 301 5-300 3 = 0 5 Using Table A the...

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Stat 145: Exam 1 Review Answers 1. (a) Roughly 100 students had less than \$20 in their possession (add the heights of the bars to the left of 20). (b) The distribution is skewed to the right. The center is between 10 and 20. The data ranges from a low of about 0 to a high of about 110 with the outlier and a low of about 0 to a high of about 60 without the outlier. ( Note: If the distribution contains outliers, you should give the spread with and without the outliers. ) (c) The standard deviation will decrease, as removing the outlier will decrease the spread of the data. 2. (a) The z -value is: z = 305 - 300 3 . = 1 . 67 Using Table A, the answer is 1 - . 9525 = . 0475, or 4.75%. (b) The z -values are: z 1 = 297 - 300 3 = - 1

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Unformatted text preview: z 2 = 301 . 5-300 3 = 0 . 5 Using Table A, the answer is . 6915-. 1587 = . 5328, or 53.28%. (c) The area to the left of x is .25. The closest value to .25 in the body of Table A is z =-. 67. Thus, x-300 3 =-. 67 x-300 = 3(-. 67) x = 300 = 3(-. 67) x . = 298 3. The mean is: ¯ x = 80 + 90 + 100 3 = 90 The standard deviation is: s = r (80-90) 2 + (90-90) 2 + (100-90) 2 3-1 = r 200 2 = √ 100 = 10 4. (a) Split stems should be used in the stemplot. 19 9 20 023 20 7889 21 0000234 21 578 22 1 (b) The ﬁve-number summary is: 199 207 210 214 221. 5. (a) Group 1 had the larger median pulse rate. (b) Between 75 ( Q 1 ) and 110 ( Q 3 )....
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This homework help was uploaded on 04/02/2008 for the course STAT 145 taught by Professor Allstats145 during the Summer '07 term at New Mexico.

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Exam 1 Answers - z 2 = 301 5-300 3 = 0 5 Using Table A the...

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