Thirty women were examined in a hospital by a doctor and the number of heart beats per minute recorded and summarized as follows. Find the mean heart beats per minute for these women, choosing a suitable method.
Number of heart Beats Per minute: 65 – 68 68 – 71 71 – 74 74 – 77 77 – 80 80 – 83 83 – 86
Number of women: 2 4 3 8 7 4 2
Answers
STEP DEVIATION METHOD:
Step deviation method is used in the cases where the deviation from the assumed mean 'A' are multiples of a common number. If the values of ‘di’ for each class is a multiple of ‘h’ the calculation become simpler by taking ui= di/h = (xi - A )/h
Here, h is the class size of each class interval.
★★ Find the class marks of class interval. These class marks would serve as the representative of whole class and are represented by xi.
★★ Class marks (xi) = ( lower limit + upper limit) /2
★★ We may take Assumed mean 'A’ to be that xi which lies in the middle of x1 ,x2 …..xn
MEAN = A + h ×(Σfiui /Σfi) , where ui = (xi - A )/h
FREQUENCY DISTRIBUTION TABLE IS IN THE ATTACHMENT
From the table : Σfiui = 4 , Σfi = 30
Let the assumed mean, A = 75.5, h = 3
MEAN = A + h ×(Σfiui /Σfi)
MEAN = 75.5 + 3 (4/30)
= 75.5 + 4/10
= 75.5 + ⅖
= 75.5 + 0.4
Mean = 75.9
Hence, the mean heart beats per minute for women is 75.9 .
HOPE THIS ANSWER WILL HELP YOU….
Answer:
mean = 75.9
Step-by-step explanation:
according to the given data the mean of the heart beat of women are 75.9