TI-Nspire CX II field manual for IB Math

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Two-sample t-test

Maths AI

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

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.

From the Scratchpad calculator, press → 6: Statistics → 7: Stat Tests → 4: 2-Sample t Test. Set Data Input Method to Stats.

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

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

t≈1.48 and p≈0.152, 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
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
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
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.