BU1007 statistics assignment due 31

# BU1007 statistics assignment due 31 - ` BU1007 statistics...

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` BU1007 statistics assignment n0.2 Question1. (10 marks) Solution (i) For this problem μ=11minutes, σ=3minutes, largest samples n=100 customers observed a) Pr( By using Z equation X transformed into Z Hence, the chance is pr[X>13] =0.0000 Figure 1 b) Pr(X<9) by using the transformation of X to Z. Pr [Z<6.67] =0.5-0.49999999 = 0.00000001

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Figure 2 (ii) Solution. X=400, σ=\$40, \$6 Pr [0<Z<3] = 0.4987+0.4987=0.9974 The probability that the mean will be within \$6 of true mean μ is Pr [-3<Z<3) = \$0.9974 Figure 3 (iii) Solution. X= 147mm, s= 10mm, n=10
Step in computing confidence interval for μ when σ is unknown, Step 1. The sample mean X= 147mm Step 2. Compute Se(X) Step 3. Here the degree of freedom in df(20-1)=19. Since α=0.05 α/2=0.025. The critical value of t such that then, table A.7 (p.858), critical values from the then read df =19. The intersection between these insides body of the table gives the critical values which is 2.093. Step 4. 95% confidence interval for μ. Hence, 95% of the sample size n=20 produce 95% confidence interval that population mean fall in this interval [142.32mm, 151.68mm]. See figure. 4 (iv) Solution 1. Random sample n=100 x=60 Step 2 standard error Step 3. The critical values Step 4. 90% confidence interval for p:

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## This note was uploaded on 01/17/2012 for the course BUSINESS BU2005 taught by Professor Smith during the Three '10 term at Bond College.

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BU1007 statistics assignment due 31 - ` BU1007 statistics...

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