The mean of a sample a. is always equal to the mean of the population.
b. is always smaller than the mean of the population.
c. is computed by summing all the data values and dividing the sum by the number of items.
d. is computed by summing the data values and dividing the sum by (n - 1).

c. is computed by summing all the data values and dividing the sum by the number of items.

Step-by-step explanation:

Mean is said to be the average of the entire data set. Even in case when data set is too large we choose to calculate the mean of sample. In that case, sum up all the data of sample and divide by the number of items.

For example:

There are 50 students in the class, but some students are not present, some are not in the class, to collect information from all students is not feasible, in that case.

The data of some random 10 students is taken, example to check the proficiency in mathematics their scores in last class test are summed up, and divided by number of students considered.

That is sum of marks obtained by 10 students divided by 10, will provide the mean.  

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step-by-step explanation:

1+2+3+4+5+6+7+8+9+10 = 55

2*10 = 20

55-20 = 35

b