Standard +0.3 This is a straightforward one-sample z-test for a mean with given population standard deviation. It requires standard hypothesis testing procedure (stating hypotheses, calculating test statistic, comparing to critical value) but involves no conceptual challenges beyond routine application of the normal distribution and significance testing framework taught in Stats 1.
In the past, the time spent in minutes, by customers in a certain library had mean 32.5 and standard deviation 8.2.
Following a change of layout in the library, the mean time spent in the library by a random sample of 50 customers is found to be 34.5 minutes.
Assuming that the standard deviation remains at 8.2, test at the 5% significance level whether the mean time spent by customers in the library has changed. [7]
In the past, the time spent in minutes, by customers in a certain library had mean 32.5 and standard deviation 8.2.
Following a change of layout in the library, the mean time spent in the library by a random sample of 50 customers is found to be 34.5 minutes.
Assuming that the standard deviation remains at 8.2, test at the 5% significance level whether the mean time spent by customers in the library has changed. [7]
\hfill \mbox{\textit{OCR H240/02 2017 Q10 [7]}}