Answer:
Step-by-step explanation:
1. The null hypothesis contains “equal” sign (“=” or “≥” or “≤”), the alternative hypothesis is the complement to the null hypothesis. The claim is “the mean life of a certain type of light bulb is at least 1000 hours”. As the claim contains “≥” sign, it is null hypothesis.
H0: µ ≥ 1000
Alternative hypothesis:
The alternative hypothesis is the complement: “the mean life of a certain type of light bulb is less
than 1000 hours”.
Ha: µ < 1000
b. As the alternative hypothesis contains “<” sign, the test is left-tailed. Using α = 0.02, we obtain critical value from standard table of normal distribution:
z0 = -1.54
Thus, the rejection region for the test statistic is z < -1.54.
