hypothesis test

True or False: Referring to the table below, the null hypothesis will be rejected.
An appliance manufacturer claims to have developed a compact microwave oven that
consumes an average of no more than 250 Watts. From previous studies, it is believed that power consumption for microwave ovens is normally distributed with a standard deviation of 15 Watts. A consumer group has decided to try to discover if the claim appears true at .05 level of significance. They take a sample of 20 microwave ovens and find that they consume an average of 257.3 Watts.


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I have got the following

z-value 2.1764
one-tailed p-value 0.0148

95% confidence internvals
upper Inf
lower 244.483

Reject Null


Is the ans correct?