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Quiz # 2 04/15/
Name:
Directions: Make sure to read each problem carefully. Make sure to show all of your work to receive full credit.
Problem 1. Suppose a school administers a test to its students measuring intelligence. The resulting data is normally distributed with μ = 105, σ = 8. What proportion of students scored between 89 and 109? (Make sure to show your work or provide an explanation) (a) about .4635% (b) about 46.35% (c) about 66.87% (d) about 71.43% (e) about 95% (f) cannot be determined from the information given (g) none of the above
Problem 2. Suppose a school on Mars administers a test to its students measuring in- telligence. The resulting data is left skewed with μ = 78, σ = 14. What proportion of participating Martians scored better than 50? (Make sure to show your work or provide an explanation) (a) about .9772% (b) about 2.28% (c) about 50% (d) about 95% (e) about 97.72% (f) cannot be determined from the information given (g) none of the above
Problem 3. Suppose that two tall Martians named Ned and Nina were arguing as to which one’s height was more extraordinary given their genders. (Martians measure height in ”quig- gles” which are abbreviated q.) The height of male Martians is normally distributed with mean μm = 55. 2 q and standard deviation σm = 3 q, and the height of female Martians is normally distributed with mean μf = 57. 3 q and standard deviation σf = 3. 2 q. If Ned has height 64. 3 q and Nina has height 67. 5 q who is correct in this argument?
Problem 4. In a study, 10 Martians had their height and foot length measured (in quiggles of course). Here is what they came up with:
height 53 54 54 55 56 56 58 59 59 61 foot length 25 23 24 22 20 18 17 16 14 15 (a) Make a scatterplot of this data with height as the explanatory (independent) variable and foot length as the response (dependent) variable.
(b) From viewing this graph, does it appear that height and foot length are strongly correlated? If so, is the relationship between height and foot length negative or positive?
