1 Proportion

 

Overview  |  How to  |  Data  |  Example

 

 

 

Overview

 

The 1 Proportion conducts a hypothesis test and calculates a confidence interval of the population proportion.  It is a test of one binomial proportion.

 

Test

Null Hypothesis, H0

Alternate Hypothesis, H1

One-tailed

p = p0

p < p0 or p > p0

Two-tailed

p = p0

p ¹ p0

 

where p is the population proportion and p0 is the hypothesised value

 

 

 

 

 

How to

 

1.       Choose ProcessMA > Basic Statistics > 1 Proportion.

 

2.       In Data in, choose how your data is stored.

 

·         If your data in stored in a single column:

 

-         In Variable, select the column containing the raw data

 

·         If your data in stored in summarised data:

 

-         In Number of trials, enter the number of trials.

 

-         In Number of successes, enter the number of successes within the set of trials.

 

3.       In Test proportion, enter the hypothesised proportion.

 

4.       Click OK.

 

 

Optional

 

5.       In Alternate, select the type of test.

 

6.       In Confidence level, enter the desired confidence level for the confidence interval.

 

 

Note       To select a column of data into a textbox, double-click on any of the column names shown in the list on the left of the dialog box while in the textbox.

 

 

 

 

 

Data

 

Variable: Text or numeric; Must contain 2 distinct categories (e.g. Pass and Fail, 0 and 1)

 

Number of trials: Integer.

 

Number of successes: Integer.

 

Test proportion: Numeric; Between 0 and 1

 

Confidence level: Numeric; Between 0 and 100.

 

 

 

 

 

Example

 

A telecommunication company recently launched a new customer help service.  The company conducted a customer survey to find out if customer satisfaction has improved from last year’s 68%.  860 customers were randomly selected for the survey and of which 590 were satisfied. 

 

1.       Choose ProcessMA > Basic Statistics > 1 Proportion.

 

2.       In Data in, select summarised data.

 

3.       In Number of trials, enter 860.

 

4.       In Number of successes, enter 590.

 

5.       In Test proportion, enter 0.68.

 

6.       In Alternate, select Greater than.

 

7.       In Confidence level, enter 95.

 

8.       Click OK.

 

 

 

 

Interpretation

 

For a desired a = 0.05, since p = 0.3519 > a, we fail to reject H0.  Therefore, we conclude that there is no significant evidence that customer satisfaction has improved.