Lesson 9.3 Day 2

Did you sleep with a comfort object as a child? Do you still? No need to stuff that teddy bear from your infant years in your closet the next time you have a guest over—the odds are good that he or she has a comfort object, too. A study conducted by Sleepopolis and OnePoll reported that 34% of adults still sleep with a stuffed animal, blanket, or other sentimental object, according to a survey of a random sample of 100 adults. A similar study, based on a random sample of 80 children reports that 75% of children sleep with a comfort object.

Do these data provide convincing evidence that the proportion of adults who sleep with a comfort object is less than the proportion of children who sleep with a comfort object? Justify your answer.

Which are the correct hypotheses for the significance test?

• Ho: p1 - p2 = 0

  Ha: p1 - p2 does not equal 0

  where p1-p2 = the true difference in proportion of adults and children who sleep with a comfort object (adults - children) using α = 0.05

• Ho: p1 - p2 = 0

  Ha: p1 - p2 > 0

  where p1-p2 = the true difference in proportion of adults and children who sleep with a comfort object (adults - children) using α = 0.05

• Ho: p1 - p2 = 0

  Ha: p1 - p2 < 0

  where p1-p2 = the true difference in proportion of adults and children who sleep with a comfort object (adults - children) using α = 0.05

Did you sleep with a comfort object as a child? Do you still? No need to stuff that teddy bear from your infant years in your closet the next time you have a guest over—the odds are good that he or she has a comfort object, too. A study conducted by Sleepopolis and OnePoll reported that 34% of adults still sleep with a stuffed animal, blanket, or other sentimental object, according to a survey of a random sample of 100 adults. A similar study, based on a random sample of 80 children reports that 75% of children sleep with a comfort object.

Do these data provide convincing evidence that the proportion of adults who sleep with a comfort object is less than the proportion of children who sleep with a comfort object? Justify your answer.

Which is the correct "Plan" for the significance test?

• Two sample z test for p1 - p2

  
  

  Random samples of 100 adults and 80 children

  100 < 1/10(all adults) 80 < 1/10(all children)

  100(.34) = 34; 100(.66) = 66; 80(.75)=60; 80(.25) = 20 all at least 10.

• Two sample z test for p1 - p2

  
  

  Random samples of 100 adults and 80 children

  100 < 1/10(all adults) 80 < 1/10(all children)

  100(.522) = 52.2; 100(.478) = 47.8; 80(.522)=41.8; 80(.478) = 38.2 all at least 10.

• Two sample z test for p1 - p2

  
  

  100 adults and 80 children randomly assigned

  
  

  100(.522) = 52.2; 100(.478) = 47.8; 80(.522)=41.8; 80(.478) = 38.2 all at least 10.

• Two sample z test for p1 - p2

  
  

  100 adults and 80 children randomly assigned

  100(.34) = 34; 100(.66) = 66; 80(.75)=60; 80(.25) = 20 all at least 10.

Did you sleep with a comfort object as a child? Do you still? No need to stuff that teddy bear from your infant years in your closet the next time you have a guest over—the odds are good that he or she has a comfort object, too. A study conducted by Sleepopolis and OnePoll reported that 34% of adults still sleep with a stuffed animal, blanket, or other sentimental object, according to a survey of a random sample of 100 adults. A similar study, based on a random sample of 80 children reports that 75% of children sleep with a comfort object.

Do these data provide convincing evidence that the proportion of adults who sleep with a comfort object is less than the proportion of children who sleep with a comfort object? Justify your answer.

Which is the correct test statistic for this significance test?

• -6.29

• 6.29

• 5.46

• -5.46

Did you sleep with a comfort object as a child? Do you still? No need to stuff that teddy bear from your infant years in your closet the next time you have a guest over—the odds are good that he or she has a comfort object, too. A study conducted by Sleepopolis and OnePoll reported that 34% of adults still sleep with a stuffed animal, blanket, or other sentimental object, according to a survey of a random sample of 100 adults. A similar study, based on a random sample of 80 children reports that 75% of children sleep with a comfort object.

Do these data provide convincing evidence that the proportion of adults who sleep with a comfort object is less than the proportion of children who sleep with a comfort object? Justify your answer.

What is the correct conclusion to this significance test?

• Because the the p-value of 0 < α = 0.05, we reject the Ho. We have convincing evidence that the proportion of adults who sleep with comfort objects is less than the proportion of children who sleep with comfort objects.

• Because the the p-value of 0 < α = 0.05, we fail reject the Ho. We do not have convincing evidence that the proportion of adults who sleep with comfort objects is less than the proportion of children who sleep with comfort objects.

• Because the the p-value of 0 < α = 0.05, we accept the Ho. We do not have convincing evidence that the proportion of adults who sleep with comfort objects is less than the proportion of children who sleep with comfort objects.