1. Section 7.1
Day 3

2. Quiz when ?
no note card
terminology & sample distribution

3. A parameter is __________________.

4. A parameter is a summary number describing a population.

5. A statistic is ____________________.

6. A statistic is a summary number calculated from a sample taken from a population.

7. A sampling distribution is ______________.

8. A sampling distribution is the distribution of a sample statistic in repeated random samples of the same fixed size, n.

9. P5, page 419

10. P5 (a)

11. P5 (a) L1
STAT
CALC
1: 1-Var Stats

12. P5 (a) 1- Var Stats x = 261.8 ∑x = 1309 ∑x2 =490351 Sx = 192.1293835

13. P5(a) 1- Var Stats x = 261.8 population mean ∑x = 1309 ∑x2 =490351
σx = population standard deviation

14. P5

15. P5(c) 1- Var Stats x = 261.8 ∑x = 2618 ∑x2 = 796133.5 Sx = 110.9259513

16. P5 1- Var Stats x = 261.8 sampling distribution mean ∑x = 2618
σx = standard error

17. P5 (c)
(c) The mean of the sampling distribution is 261.8, which is exactly the mean of the population.
So, the sample mean is an unbiased estimator of the population mean.

18. P5 (d)

19. E5, page 422

20. E5, page 422

21. E5, page 422
b. 62, 63, 64, 64, 65
62 and and and 64
62 and and and 65
62 and and and 65
62 and 65

22. E5, page 422 c. In the same order as the samples listed in
part b, their means are 62.5, 63, 63, 63.5,
63.5, 63.5, 64, 64, 64.5, and 64.5.

23. E5, page 422 The exact sampling distribution of the
sample mean for samples of size 2 is shown
in this dot plot.

24. E5, page 422 The sampling distribution has a mean of
63.6 and a standard error of about
The population has a mean of 63.6 and a
standard deviation of about
The two means are exactly the same and,
as usual, the standard error is smaller than
the standard deviation of the population.

25. E5, page 422

26. E5, page 422

27. P1, p. 418

28. P1, p. 418

29. P1

30. P1

31. P1, p. 418 1 2 3 4 5 6 7 8
MATH
PRB
randInt(1, 8)
No repeat in sample

32. P1

33. P1

34. P2 (a), Page 418

35. P2 (a) I is B, which is irregular in shape and has
a spread nearly as large as the spread of
the population.
II is A, which is somewhat mound-shaped
with a narrower spread.
III is C, which is mound-shaped and has a
very narrow spread.
All of these distributions have centers very close to
the center of the population.

36. P4, page 419

37. P4 (a)

38. P4

39. P4b (con’t)

40. P(paid $3 million or more)
12/15

41. E1

42. E1, Page 420 a. Histogram A has sample size of 20.
Histogram B has sample size of 1.
Histogram C has sample size of 2.
Histogram D has sample size of 50.
As sample size increases, spread decreases.

43. E1 b. The means all appear to be in the neighborhood of 4.5.
Sample size does not appear to affect the
mean.

44. E1
c. The larger the sample size, the smaller the spread.

45. P6, page 420

46. P6, page 420
a. The population parameter we are estimating is the population range.
Range = max – min
= 527 – 56
= 471 mi2

47. P6

48. P6

49. E9, page 423

50. E9

51. E9 (con’t)

52. Questions?
Quiz tomorrow