Harley-Davidson Stock Volume The trade volume of a stock is the number of shares traded on a given day. The following data, in millions (so that 2.45 represents 2,450,000 shares traded), represent the volume of Harley-Davidson stock traded for a random sample of 40 trading days in 2010.
|
2.45
|
2.10
|
7.11
|
2.91
|
1.92
|
1.45
|
2.31
|
1.41
|
|
1.62
|
4.48
|
2.30
|
1.42
|
3.26
|
2.82
|
1.66
|
2.30
|
|
1.58
|
1.91
|
1.67
|
2.66
|
1.47
|
1.14
|
3.06
|
3.09
|
|
2.83
|
1.77
|
1.50
|
6.19
|
2.84
|
1.94
|
2.02
|
1.71
|
|
1.87
|
1.83
|
2.03
|
2.62
|
1.81
|
1.89
|
1.64
|
0.89
|
(a) Use the data to compute a point estimate for the population mean number of shares traded per day in 2010.
(b) Construct a 90% confidence interval for the population mean number of shares traded per day in 2010. Interpret the confidence interval.
(c) A second random sample of 40 days in 2010 resulted in the data shown next. Construct another 90% confidence interval for the population mean number of shares traded per day in 2010. Interpret the confidence interval.
|
2.07
|
2.39
|
1.24
|
2.02
|
2.23
|
1.67
|
2.06
|
2.74
|
|
5.19
|
2.38
|
3.32
|
2.44
|
2.34
|
2.74
|
1.37
|
1.60
|
|
1.71
|
1.64
|
2.20
|
1.43
|
1.48
|
2.05
|
3.75
|
3.30
|
|
2.70
|
2.44
|
1.67
|
1.38
|
3.12
|
1.69
|
1.79
|
2.05
|
|
3.59
|
1.79
|
2.20
|
1.54
|
0.84
|
2.19
|
1.69
|
1.77
|
(d) Explain why the confidence intervals obtained in parts (b) and (c) are different.