- Page 428:
- Check the conditions: 7b, 11, 23 (conditions only!)
- Normal Model Review: 25ab
- Also do #1abd
- For a,b...think! You got this!
- For 1d we're asked why we can't use a Normal model here--that's because one of the 3 conditions for a sampling distribution for proportions fails....to answer 1d, state/show which of the 3 conditions fails
And here are the homework answers so you can check:
7b.) This is a sampling distribution for proportions. It is not stated if this is a random sample of 80 cars--proceed with caution. 80 cars is less than 10% of all cars on this major interstate highway. Finally (80)(0.7)>10 and (80)(0.3)>10.
11.) This is a sampling distribution for proportions. It is not stated if the freshman classes (of 400 students) will be selected randomly, proceed with caution. 400 college freshman is less than 10% of all college freshmen. Finally, (400)(0.74)>10 and (400)(1 - 0.74)>10.
23.) This is a sampling distribution for means. It is stated that students were randomly assigned to writing seminars (of size 25). It's also stated that the distribution was mound shaped and symmetric, but a sample size of 25 is also large enough. Finally, 25 students is likely less than 10% of all incoming freshmen at this school.
1d) A Normal model should not be used because np = (16)(0.5) = 8, which is not bigger than 10!
1ab) Think! You're on your own! (Or check the back of your book)
25a) 21.1%
25b) 276.8 days (or more)
7b.) This is a sampling distribution for proportions. It is not stated if this is a random sample of 80 cars--proceed with caution. 80 cars is less than 10% of all cars on this major interstate highway. Finally (80)(0.7)>10 and (80)(0.3)>10.
11.) This is a sampling distribution for proportions. It is not stated if the freshman classes (of 400 students) will be selected randomly, proceed with caution. 400 college freshman is less than 10% of all college freshmen. Finally, (400)(0.74)>10 and (400)(1 - 0.74)>10.
23.) This is a sampling distribution for means. It is stated that students were randomly assigned to writing seminars (of size 25). It's also stated that the distribution was mound shaped and symmetric, but a sample size of 25 is also large enough. Finally, 25 students is likely less than 10% of all incoming freshmen at this school.
1d) A Normal model should not be used because np = (16)(0.5) = 8, which is not bigger than 10!
1ab) Think! You're on your own! (Or check the back of your book)
25a) 21.1%
25b) 276.8 days (or more)
Tomorrow it's back to sampling distributions--and finally some math! See you there!
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