Student s t Distribution Lecture 35 Section 10 2 Robb T Koether Hampden Sydney College Wed Mar 24 2010 Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 1 32 Outline 1 Introduction 2 The Decision Tree 3 The t Test on the TI 83 4 Testing for Normality 5 Assignment Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 2 32 Outline 1 Introduction 2 The Decision Tree 3 The t Test on the TI 83 4 Testing for Normality 5 Assignment Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 3 32 Introduction We now have three different tests of hypotheses Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 4 32 Introduction We now have three different tests of hypotheses I 1 sample z test of proportions 1 PropZTest Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 4 32 Introduction We now have three different tests of hypotheses I I 1 sample z test of proportions 1 PropZTest 1 sample z test of means Z Test Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 4 32 Introduction We now have three different tests of hypotheses I I I 1 sample z test of proportions 1 PropZTest 1 sample z test of means Z Test 1 sample t test of means T Test Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 4 32 Introduction We now have three different tests of hypotheses I I I 1 sample z test of proportions 1 PropZTest 1 sample z test of means Z Test 1 sample t test of means T Test We need to be careful when deciding which test to use Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 4 32 Introduction We now have three different tests of hypotheses I I I 1 sample z test of proportions 1 PropZTest 1 sample z test of means Z Test 1 sample t test of means T Test We need to be careful when deciding which test to use It takes practice Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 4 32 Outline 1 Introduction 2 The Decision Tree 3 The t Test on the TI 83 4 Testing for Normality 5 Assignment Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 5 32 The Decision Tree Is known yes no Is the population normal yes Z Come back later no X n Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Give up Student s t Distribution Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes no Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Give up Student s t Distribution Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no yes no Give up Student s t Distribution Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes no X s n Z T T Student s t Distribution Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes no X X T s n s n Z T T Student s t Distribution Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes Is n 30 no yes no X X T s n s n Z T T Student s t Distribution Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes Is n 30 no X X T s n s n Z T T Student s t Distribution yes Z no X s yes n Wed Mar 24 2010 6 32 The Decision Tree Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes Is n 30 no X X T s n s n Z T T Student s t Distribution yes Z no X s yes n Give up Wed Mar 24 2010 6 32 When to Use Z Which statistic Use z when is known and the population is normal no matter how small the sample Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 7 32 When to Use Z Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes Is n 30 no X X T s n s n Z T T Student s t Distribution yes Z no X s yes n Give up Wed Mar 24 2010 8 32 When to Use Z Which statistic Use z when the population is not normal but the sample size is large whether or not is known Robb T Koether Hampden Sydney College Student s t Distribution Wed Mar 24 2010 9 32 When to Use Z Is known yes no Is the population normal yes Z Is the population normal no X n yes Is n 30 yes Z X n Robb T Koether Hampden Sydney College no Is n 30 no Give up yes Is n 30 no X X T s n s n Z T T Student s t Distribution yes Z no X s yes n Give up Wed Mar 24 2010 10 32 When to Use t Which statistic Use t when is not known and the population is normal no matter how large or small the sample If the sample size is small then we must use t If the sample size is large then we may use z instead of t Robb T Koether Hampden Sydney College …
View Full Document
Unlocking...