Answer:
a) 75.62
b) 75.2
Step-by-step explanation:
Data provided:
79.9,75.1,78.2,74.1,73.9,75.0,77.6,77.3,73.8,74.6,75.5,74.0,74.7,75.9,72.6,73.8,74.2,78.1,75.4,76.3,75.3,76.2,74.9,78.0,75.1,76.8
Sum = 1966.3
Total number of observations, n = 26
a) Mean is given as:
Mean = 
or
Mean = 
or
Mean = 75.62
b) For value that separates the weakest 50% of the connectors i.e median or the 50th percentile
Arranging the data in ascending order:
72.6, 73.8, 73.8, 73.9, 74, 74.1, 74.2, 74.6, 74.7, 74.9, 75, 75.1, 75.1, 75.3, 75.4, 75.5, 75.9, 76.2, 76.3, 76.8, 77.3, 77.6, 78, 78.1, 78.2, 79.9
i = 
or
i =
= 13
When the number of observations is even the formula for median is:

or

or

or

or
Median = 75.2