gold 0.64 0.88 0.69 0.47 0.43 0.42 1.37 0.59 0.94 0.79 0.81 0.28 0.26 0.23 0.74
ID: 3075302 • Letter: G
Question
gold
0.64
0.88
0.69
0.47
0.43
0.42
1.37
0.59
0.94
0.79
0.81
0.28
0.26
0.23
0.74
0.59
0.82
0.51
0.58
0.83
0.38
0.46
1.26
0.65
1.40
1.51
1.16
0.50
1.16
1.68
0.89
0.96
0.75
0.84
0.26
1.40
0.54
0.17
0.43
0.23
0.47
0.66
0.75
0.26
0.14
0.34
0.51
1.67
0.81
0.65
0.46
0.30
0.84
0.14
0.70
0.89
0.72
0.20
0.35
0.39
1.23
0.53
0.25
0.71
1.21
0.35
0.14
0.69
0.48
0.15
0.42
0.78
0.15
0.50
1.19
0.53
3.78
0.36
2.16
0.95
0.68
0.63
0.63
0.94
0.66
0.62
0.27
0.24
3.24
0.92
1.25
1.48
0.54
0.53
0.32
0.53
0.70
0.28
0.51
3.87
1.65
1.59
0.87
1.96
0.81
0.75
1.49
0.59
0.58
0.69
1.58
0.82
0.27
0.59
0.49
0.36
3.12
0.53
0.84
0.88
0.60
0.32
0.80
1.19
0.45
0.37
0.91
0.30
1.40
0.64
1.20
0.89
0.60
1.39
0.73
0.36
0.22
0.31
0.49
0.60
0.42
1.40
0.31
0.38
0.36
0.83
0.95
0.70
0.97
0.70
1.23
0.65
0.45
0.71
1.67
2.32
1.17
0.78
0.16
0.42
0.22
2.00
0.83
0.94
0.48
0.44
0.22
0.52
0.61
1.14
0.14
0.48
0.76
0.88
2.27
1.20
1.08
0.37
0.36
0.38
1.10
7. The data in gold.txt are gold grades (ppm) of a sample of 181 drill cores from a mine in Canada. Denote the grades by ai, for i = 1, 181. (a) Calculate the mean (), median (med), and standard deviation (sx of the grades (b) What proportion of grades lie within x ± s? (c) Take natural (base e) logarithms of the data to obtain yi where Vi = In(m). Calculate the mean (j), median (med.), and standard deviation (sy) of the logarithms of the grades (d) Compare ln(T) with (7) and comment. (e) Compare In(medzx) with (medy) and comment. (f) Assume the logarithms of grade have a normal distribution and esti- mate the upper 0.01 quantile in the corresponding population of all possible logarithms of grades from this mine by +1normino(.99)]sy (g) Hence calculate the upper 0.01 quantile of the distribution of all gradesExplanation / Answer
a)
b)
151 /181 = 0.834254
c)
d)
ln (Xbar) = -0.233
we see that ln (xbar) < ybar
e)
ln (med_x) = -0.43078
both are equal as median is fixed value and hence transormation does not change it
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