Descriptive Statistics for student study hours at a campus

Suppose you have drawn a simple random sampleof 10 students from a college campus and recorded how many hours each student studies (X) during the first week of December,
2009. Results:

Student # 1 2 3 4 5 6 7 8 9 10
Hours Studied: 10 15 20 5 0 18 12 18 7 15

For this sample, compute PXi, the sample average (X), P(Xi¡X)2, and the sample standard deviation(s).

Step by step method for computing standard deviation is given in the answer.