The study seeks to test the life of batteries of the new iPhone. The study hypothesizes that the batteries of the phone can last at least eight hours on 4G with standard usage. In this scenario, a sample of 25 phones is randomly selected from the iPhone distribution centres. Each category has five phones. Random sampling is chosen for the study to minimize the probability of biasness since each iPhone has an equal chance of being selected. According to descriptive statistics, the mean value as far as the iPhone batteries are concerned is 6.608 with a median of 6.5 as well as a standard deviation of 1.31. Based on the small standard deviation value, it means that the values are closely distributed around the mean. MS excel gives the following data for the study:
| Mean |
6.608 |
| Standard Error |
0.262673435 |
| Median |
6.5 |
| Mode |
5 |
| Standard Deviation |
1.313367174 |
| Sample Variance |
1.724933333 |
| Kurtosis |
-1.188251072 |
| Skewness |
0.148104544 |
| Range |
4.5 |
| Minimum |
4.5 |
| Maximum |
9 |
| Sum |
165.2 |
| Count |
25 |
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T-test method is applied in testing the hypothesis that the mean life of the batteries is at least 8 hours. The null and alternative hypothesis used is H0: and H1: , respectively. The test is a left tail test with a significance level of 0.05. The formula below is used to determine the t-stat value;
At t-stat value of -5.31 the P-Value is < 0.00001. The P-value is less than the significance level (P <0.05). From the test, the null hypothesis is rejected, and a conclusion reached that the average life of the new iPhone batteries is less than 8 hours on 4G with standard usage.
