Question
In: Statistics and Probability
An air-conditioning supplier uses two installers. He is interested in comparing the time each installer takes...
An air-conditioning supplier uses two installers. He is interested in comparing the time each installer takes to install an air-conditioning unit. Data concerning installation times was collected over a period of time, and the following results were determined. (Note: the installation times are in hours).
| Sample Mean | Sample Standard Deviation | Sample Size | |
| Installer A | 3 | 1.1952 | 8 |
| Installer B | 4 | 1.4142 | 7 |
Is there evidence, at the 5% level of significance, of a difference in the average time of installation between the two installers? (You may assume that all installation times are normally distributed, and Installer A and Installer B have equal population variances). You may use the following Excel output.
t-Test: Two-Sample Assuming Equal Variances
| Installer A | Installer B | |
| Mean | 3 | 4 |
| Variance | 1.429 | 2.000 |
| Observations | 8 | 7 |
| Pooled Variance | 1.692 | |
| Hypothesized Mean Difference | 0 | |
| df | 13 | |
| t Stat | -1.485 | |
| P(T<=t) one-tail | 0.081 | |
| t Critical one-tail | 1.771 | |
| P(T<=t) two-tail | 0.161 | |
| t Critical two-tail | 2.160 |
Solutions
orchestra answered 2 years agoRelated Solutions
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