Question

A chain of sports shops catering to beginning skiers, headquartered in Aspen, Colorado, plans to conduct a study of how much a beginning skier spends on her initial purchase and supplies. Based on these figures, to explore the possibility of offering combinations, such as a pair ofboots pair skis, induce customers to buy more. As of cash register receipts revealed these initial purchases:$85 $139 $161 $175 $85 $133 $149 $145 $136 131 290235 132 149 322 214 105 90 162 229 121 113 149 126139 118 156 214 172 87 172 230 195 126 128 142 118 139(a) Find the smallest class interval, use five classes.(b) What would be a better class interval?

Answer 1

47.4 ;

50

Explanation:

Given the data :

X ($) : 85 139 161 175 85 133 149 145 136 131 290 235 132 149 322 214 105 90 162 229 121 113 149 126139 118 156 214 172 87 172 230 195 126 128 142 118 139

The smallest class interval :

Range / number of classes

Number of classes to use = 5

Range = Maximum - Minimum = (322 - 85) =237

Hence, smallest class interval :

237 / 5 = 47.4

A better class interval would be, one without decimal, rounded to the nearest 10; this will be easier and make more statistical sense

Hence, smallest class interval rounded to the nearest 10 :

47.4 = 50 (nearest 10)