Business Statistics using Excel by Unknown

Author:Unknown
Language: eng
Format: epub

➜ Excel Solution

Signifi cance level Cell E10

Value = 0.05

Population mean Cell E13

Value = 100

Population standard deviation Cell E14

Value = 20

Sample size n Cell E16

Value = 36

Sample mean Xavg Cell E17

Value = 90

Sample standard error Cell E18

Formula = E14/E16^0.5

Z Cell E19

Formula = STANDARDIZE(E17,E13,E18)

cal

Two tail p-value Cell E22

Formula = 2*(1−NORM.S.DIST(ABS(E19),TRUE))

Lower Z = Cell E23

Formula = NORM.S.INV(E10/2)

cri

Upper Z = Cell E24

Formula = NORM.S.INV(1-E10/2)

cri

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2/7/2013 4:48:02 PM

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Business statistics using Excel

Excel solution using the p-value for a one sample z-test

To use the p-value statistic method to make a decision:

1 State hypothesis

Null hypothesis H : μ = 100 (population mean is equal to 100 units per hour).

0

Alternative hypothesis H : μ ≠ 100 (population mean is not 100 units per hour).

1

Th

e ≠ sign implies a two tail test.

2 Select test

We now need to choose an appropriate statistical test for testing H . From the 0

information provided we note:

• number of samples—one sample;

• the statistic we are testing—testing for a diff erence between a sample mean ( x = 90) and population mean (μ = 100). Population standard deviation is known (σ = 20);

• size of the sample—large (n = 36);

• nature of population from which sample drawn—population distribution is not known, but sample size is large. For large n, the Central Limit Th

eorem states that

the sample mean is distributed approximately as a normal distribution.

One sample z-test of the mean is therefore selected.

3 Set the level of signifi cance (α) = 0.05 (see Cell E10)

4 Extract relevant statistic

When dealing with a normal sampling distribution we calculate the Z statistic using equation (6.1):

(x

µ)

Z

=

−

cal

σ n

(6.1)

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