Q15 of 141 Page 8

If the mean of the following data is 18.75. Find the value of p.



















xi:



10



15



p



25



30



yi:



5



10



7



8



2







































X



y



yx



10



5



50



15



10



150



P



7



7p



25



8



200



30



2



60




N = 32



∑yx = 7p + 460



Given,


Mean = 18.75


= 18.75


= 18.75


7p + 460 = 18.75 (32)


7p + 460 = 600


7p = 140


p = 20


Hence, the value of p is 20


More from this chapter

All 141 →
13

The arithmetic mean of the following data is 14. Find the value of k.



















xi:



5



10



15



20



25



yi:



7



k



8



4



5


 14

The arithmetic mean of the following data is 25, find the value of k.



















xi:



5



15



25



35



45



yi:



3



k



3



6



2



[CBSE 2001]

 1

The number of telephone calls received at an exchange per interval for 250 successive one-minute intervals are given in the following frequency table.























No. of calls (x):



0



1



2



3



4



5



6



No. of intervals (f):



15



24



29



46



54



43



39



Compute the mean number of calls per interval.

 2

Five coins were simultaneously tossed 1000 times, and at each toss the number of heads was observed. The number of tosses during which 0, 1, 2, 3, 4 and 5 heads were obtained are shown in the table below. Find the mean number of heads per toss





















No. of heads pre toss(x):



0



1



2



3



4



5



No. of tosses (f):



38



144



342



287



164



25