A producer manufactures batteries by using techniques I and II. The capacities (in ampere hours) of 12 randomly selected batteries manufactured by using technique I are: 140, 132, 136, 142, 138, 150, 154, 150, 152, 136, 144, and 142. Moreover, the capacities (in ampere hours) of 14 randomly selected batteries manufactured by using technique II are: 144, 134, 132, 130, 136, 146, 140, 128, 131, 128, 150, 137, 130, and 135.
Suppose that battery capacities manufactured by using techniques I and II are normally distributed, with unknown means, \( \mu_I \) and \( \mu_{II} \) respectively, and an unknown common variance \( \sigma^2 \). Consider the null hypothesis \( H_0: (\mu_I - \mu_{II}) = \gamma \) ampere hours.
For which of the following values of \( \gamma \) should the null hypothesis \( H_0 \) be accepted against the alternative hypothesis \( H_1: (\mu_I - \mu_{II}) \neq \gamma \) ampere hours, at 10% level of significance?