Question

1) Industry Research polled teenagers on sunscreen use. The survey revealed that 46% of teenage girls and 30% of teenage boys regularly use sunscreen before going out in the sun.  

identify the two populations
A. teenage girls and teenage boys who use sunscreen regularly
B. all teenagers
C. teenage girls and teenage boys
D. None of the above


identify the specified attribute
A. being a teenage girl or a teenage boy
B. being a teenager
C. uses sunscreen before going out in the sun
D. None of the above


are the proportions 0.46 (46%) and 0.30 (30%) population proportions or a sample proportions?
A. population proportions
B. sample proportions
C. None of the above

2) Select True or False from each pull-down menu, depending on whether the corresponding statement is true or false.

  ?    True    False      1. The number of degrees of freedom associated with the ?t test, when the data are gathered from a matched pairs experiment with 10 pairs, is 9.

  ?    True    False      2. The best estimator of the difference between two population means ?1−?2 is the difference between two sample means ?¯1−?¯2x

  ?    True    False      3. In testing the difference between two population means using two independent samples, the sampling distribution of the sample mean difference ?¯1−?¯2x is normal if the sample sizes are both greater than 30.

  ?    True    False      4. A political analyst in Iowa surveys a random sample of registered Democrats and compares the results with those obtained from a random sample of registered Republicans. This is an example of two independent samples.

Answer 1

Question 1

(a) Here the two population are "Teenage boys" and "Teenage Girls".

(b) Here specific attribute is "C. uses sunscreen before going out in the sun"

(c) These are sample proportions.

Question 2

(1) The number of degrees of freedom associated with the ?t test, when the data are gathered from a matched pairs experiment with 10 pairs, is 9. TRUE

(2) The best estimator of the difference between two population means ?1−?2 is the difference between two sample means ?¯1−?¯2x. TRUE

(3) In testing the difference between two population means using two independent samples, the sampling distribution of the sample mean difference ?¯1−?¯2x is normal if the sample sizes are both greater than 30. FALSE

(4) A political analyst in Iowa surveys a random sample of registered Democrats and compares the results with those obtained from a random sample of registered Republicans. This is an example of two independent samples.FALSE