Name That Inference Procedure Directions Classify each problem

Name That Inference Procedure

• • • Directions: Classify each problem as requiring 1) a Confidence Interval or 2) a Significance Test for A single mean A proportion The difference between two independent means A paired difference The difference between two independent proportions

Will a light bulb last for more than 500 hours on average? 200 bulbs were observed.

• Significance test for a single mean

How often do first dates end with a kiss? 85 first dates were observed.

• Confidence interval for a proportion

Do math students who spend time with a tutor earn a higher class average than those who do not have a math tutor? 43 students who used a tutor and 72 students who did not use a tutor took part in the study.

• Significance test for the difference of two independent means

How much colder is it in Reno compared to Sacramento? Daily low temperatures were compared over 100 days.

• Confidence interval for paired difference (matched pairs)

Does the home team win the majority of the time? 100 games were observed.

• Significance test for a proportion

Are fewer crimes committed in an area where policemen are patrolling? 50 locations were studied for the number of crimes committed before policemen were assigned to patrol the locations and after they began patrolling.

• Significance test for a (matched) paired difference

Are males currently serving in the US Senate older than current female Senators? The birth certificates of 100 senators are examined.

• No inference procedure is necessary. We have all the data!

Are non-college teens more likely then college teens to drink alcohol? 90 college teens and 90 non-college teens were asked if they had an alcoholic beverage last weekend.

• Significance test for the difference between two proportions

How much does personal spending increase after a tax cut? 1500 people were studied before and after the tax cut.

• Confidence interval for a paired difference

What is the average voter turnout in large cities during a presidential election? A random sample of 38 cities reported their voter turnout during the last election.

• Confidence interval for a single mean (The data collected from each city is a proportion, but the confidence interval is for the mean of the cities’ voter turnouts)

Are the Japanese less likely than Americans to believe that whales are an endangered species? In a survey of 750 Japanese, 325 stated that whales are endangered, whereas a survey of 1000 Americans showed that 525 believe whales are endangered.

• Significance test for the difference between two proportions

How much larger will plants grow in artificially fertilized soil then in organic soil? 55 plants were grown in organic soil and 55 plants in artificially fertilized soil.

• Confidence interval for the difference between two (independent) means

You own a restaurant and want to find out how much lettuce is consumed on an average day. You look at total orders during each of 45 consecutive days.

• Confidence interval for a single mean

Is natural sunlight better than indoor lighting for germinating seeds? 5000 seeds were planted outside and 4000 inside to see how many would germinate.

• Significance test for the difference between proportions

How much more likely is it for a student who studies regularly to pass the AP Statistics exam than for a student who never studies? The records of 2000 students were examined.

• Confidence interval for the difference between proportions