A random sample of six salespersons that attended a motivational course on sales
ID: 3269636 • Letter: A
Question
A random sample of six salespersons that attended a motivational course on sales techniques was monitored three months before and three months after the course. The table shows the values of sales (in thousands of dollars) generated by these six salespersons in the two periods.
salesperson 123456
before the course 218 289 197 330 161 191
after the course 243 284 189 341 191 183
nbsp Salesperson nbsp
nbsp Before the Course nbsp
nbsp After the Course nbsp
1
218
243
2
289
284
3
197
189
4
330
341
5
161
191
6
191
183
Assume that the population distributions are normal. Find
a
99
%
confidence interval for the difference between the two population means.
What is the confidence interval estimate of the mean difference
(mu
afterminusmu
before)?
less than or equalsmu Subscript dless than or equalsnothing
(Round to two decimal places as needed.)
nbsp Salesperson nbsp
Explanation / Answer
From information given, n=6, dbar=-7.50, where, d=before-after and formula for computing dbar=sigma d/n=(-25+5+8-11-30+8)/6=-7.50, sd=17.10, where, sd is standard deviation of difference and is computed as sd=sqrt[1/n-1 sigma (d-dbar)^2]=sqrt[1/6-1 (-25+7.50)^2+...+(8+7.50)^2]=17.10
The df for t model is n-1=5 and 99% critical value for t5 is 4.032 [alpha=0.01, alpha/2=0.005]
Thw 99% c.i for difference between two populations, mud is: dbar+-talpha/2, df=n-2 (sd/sqt n)
=-7.50+-4.032(17.10/sqrt 6)
=(-35.65, 20.65)
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.