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TI-Nspire CX II field manual for IB Math

AI HL only · 39 of 42

39

Two-sample t-test

AI HL

Run a two-sample t-test on two sets of summary statistics to compare two population means.

Goal

Two independent groups score xˉ1=62.3,  s1=8.1,  n1=12 and xˉ2=57.8,  s2=7.4,  n2=14. Test H0:μ1=μ2 against Ha:μ1=μ2.

1

From the Scratchpad calculator, press 6: Statistics7: Stat Tests4: 2-Sample t Test. Set Data Input Method to Stats.

2

Enter both groups' summary statistics, moving between fields with , set Alternate Hyp to μ1=μ2, and check Pooled: the IB two-sample t-test assumes the two populations have equal variances, so you pool the sample variances.

Scratchpad
RAD
2-Sample t Test
x̄1:62.3
sx1:8.1
n1:12.
x̄2:57.8
sx2:7.4
n2:14.
Alternate Hyp:Ha: μ1 ≠ μ2
Pooled:Yes
OKCancel
3

Select OK and press . The test results land on the calculator page.

Result

t1.48 and p0.152, so at the 5% level there is insufficient evidence of a difference between the means.

Scratchpad
RAD
twoSampleTTest(62.3,8.1,12.,57.8,7.4,14.,0,1):stat.results
”Title””Alternate Hyp””t””PVal””df””x̄1””x̄2””sx1””sx2””sxp””n1””n2””2-Sample t Test””μ1 ≠ μ2”1.480040.15187124.62.357.88.17.47.7287112.14.

Your turn

Work each one on your calculator, then check the answer.

  1. 1

    Group 1: xˉ1=78.4,  s1=6.2,  n1=15. Group 2: xˉ2=74.9,  s2=7.1,  n2=18. Test H0:μ1=μ2 against Ha:μ1=μ2 at the 5% level.

  2. 2

    Group 1: xˉ1=12.1,  s1=1.8,  n1=10. Group 2: xˉ2=13.4,  s2=2.2,  n2=14. Test H0:μ1=μ2 against Ha:μ1=μ2 at the 5% level.

  3. 3

    Group 1: xˉ1=55.0,  s1=10.5,  n1=30. Group 2: xˉ2=58.2,  s2=9.8,  n2=28. Test H0:μ1=μ2 against Ha:μ1=μ2 at the 5% level.