Lightbulbs of a certain type are advertised as having an average lifetime of 750 hours. The price of these bulbs is very favorable, so a potential customer has decided to go ahead with a purchase arrangement unless it can be conclusively demonstrated that the true average lifetime is smaller than what is advertised. A random sample of 44bulbs was selected, the lifetime of each bulb determined, and the appropriate hypotheses were tested using MINITAB, resulting in the accompanying output.
Variable | N | Mean | StDev | SEMean | Z | P-Value |
lifetime 44 738.44 38.69 5.83 −1.98 0.024
What conclusion would be appropriate for a significance level of 0.05?
Reject the null hypothesis. There is sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
Do not reject the null hypothesis. There is not sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
Reject the null hypothesis. There is not sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
Do not reject the null hypothesis. There is sufficient evidence to conclude that the lifetime of a bulb is less than 75
What conclusion would be appropriate for a significance level of 0.01?
Reject the null hypothesis. There is sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
Do not reject the null hypothesis. There is sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
Do not reject the null hypothesis. There is not sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
Reject the null hypothesis. There is not sufficient evidence to conclude that the lifetime of a bulb is less than 750 hours.
What significance level and conclusion would you recommend and why?
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