wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

In an experiment with 250 trials, the first 150 trials has mean 16 and standard deviation 4. The overall experiment has mean 15.6 and variance 13.44.The standard deviation of the next 100 trials of given experiment is

A
3
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B
4
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
6
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
7
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is A 3
Given first 150 trials with mean ¯x=16 and standard deviation σx=4
overall 250 trials with mean ¯z=15.6 and standard deviation σ2z=13.44

Let the next 100 trials has mean ¯y and standard deviation σy
¯z=xi+yi250
xi=150×16=2400
15.6=2400+yi250yi=1500
Therefore, mean ¯y=1500100=15

σ2x=x2i150(xi150)2
16=x2i150(2400150)2
x2i=40800


σ2z=x2i+y2i250(xi+yi250)2
13.44=40800+y2i250(2400+1500250)2
y2i=23400

σ2y=y2i100(yi100)2σ2y=23400100(15)2=9
Hence the standard deviation σy=9=3

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Standard Deviation about Mean
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon