Let the five observations are 1,3,8,x,y and their mean is 5 and variance is 9.2 find the value of yx (a) 9:4 (b) 6:7 (c) 5:8 (d) none
The following are some particulars of the distribution of weights of boys and girls in a class: Boys Girls Number 100 50 Mean 60kg 45kg Variance 9 4 Which of the distributions is more variable?
The mean and standard deviation of 20 observations are found to be 10 and 2, respectively. One rechecking, it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation in each of the following cases. (i) If wrong item is omitted (ii) If it is replaced by 12.
A random survey of the number of children of various age group playing in a park was found as follows:
Draw a histogram to represent the data above.
Find the mean and variance for the following frequency distrubution
Classify the following data as primary or secondary data.
The following data gives the information on the observed lifetimes (in hours) of 225 electrical components:
|Lifetimes (in hours)||0−20||20−40||40−60||60−80||80−100||100−120|