8. Testing for Differences in Means and Proportions: Independent Samples t-test
Confidence Interval for the Difference Between Two Independent Means
Do boys and girls perform differently on driving tests? To investigate this matter, a researcher selects a simple random sample of #20# boys #(X_1)# and girls #(X_2)# and gives each of them a driving test.
Each student gets a score from #0# to #100#. These are their test results:
| Boys #(X_1)# | Girls #(X_2)# |
|
\[\begin{array}{rcl} |
\[\begin{array}{rcl} |
You may assume that the test scores are approximately normally distributed.
Construct a #99\%# confidence interval for the difference between the two population means #\mu_1 - \mu_2#. Round your answers to #3# decimal places.
#CI_{(\mu_1 - \mu_2),\,99\%}=\,(##,\,\,\, ##)#
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