## anonymous one year ago The accompanying data table lists measured voltage amounts supplied directly to a family’s home. The power supply company states that it has a target power supply of 120 volts. Using these home voltage amounts, test the claim that the mean is 120 volts. Use a 0.05 significance level. Calculate the test statistic.

1. anonymous

No one can help if you don't provide all the relevant info.

2. anonymous

Day Volts Day Volts 1 124.5 21 124.0 2 123.9 22 123.9 3 123.9 23 123.6 4 123.8 24 124.2 5 123.4 25 123.4 6 123.3 26 123.4 7 123.3 27 123.4 8 123.6 28 123.4 9 123.5 29 123.3 10 124.1 30 124.4 11 123.5 31 123.5 12 123.7 32 123.6 13 124.1 33 123.8 14 123.7 34 123.9 15 123.9 35 123.9 16 124.0 36 123.8 17 124.2 37 123.9 18 123.8 38 123.7 19 123.8 39 123.8 20 123.8 40 123.8

3. anonymous

Ugh, this isn't an incredibly user-friendly format... Anyway, the first thing to do is compute the mean of the sample, so take the average of the "Volts" data (see the pic below). We'll use a $$Z$$ test to compare this sample mean to the predicted mean. $Z=\frac{123.763-120}{0.295858}\approx12.7$

4. anonymous

If you're at all familiar with the standard normal distribution, the conclusion should be obvious, but if you're not, consult a table of $$z$$ scores, like the one linked here: http://www.rochester.edu/college/psc/clarke/201/ztable2.jpg Notice that our calculated $$Z$$ is not even listed.