solve in 15 min

The 31 items of a sample had the following values: 45, 47, 50, 52, 48, 47, 49, 53, 51, 45, 47, 50, 52, 48, 47, 49, 53, 51, 45, 47, 50, 52, 48, 47, 49, 53, 51, 45, 47, 50, 52. Does the mean of the 31 items differ significantly from as assumed normal population mean of 48.5 at 5% level of significance