Hmm the answer should be D I just had that problem not to long ago on my worksheet :)
Answer:
D) The z-statistics would be different.
Step-by-step explanation:
Confidence Interval can be calculated using M±ME where
- M is the sample mean
- ME is the margin of error from the mean
An margin of error (ME) from the mean can be calculated using the formula
ME=
where
- z is the corresponding z-statistic in the given confidence level
- s is the population standard deviation
If 95% and 98% confidence intervals were calculated from the same sample data, then M, s and N are same.
is called standard error. Since s and N are same the standard errors would also be same.
But, two tailed z-statistic for 95% confidence level is ≈1.96 where for 98% it is ≈2.33
Answer:
Assume as book to be x and pen to be y.
3x+2y=395 equation 1
2x+5y=355 equation 2
Make any variable either x or y to be equal.
3x*2+2y*2=395*2
2x*3+5y*3=355*3
Here, I am making x as same so I cross multiplied
6x+4y=790 equation 3
6x+15y=1065 equation 4
Put minus sign in any one of the equation 3 or equation 4 in order to cancel out x.
6x+4y=790
-6x-15y= -1065
0 - 11y= - 275
y= - 275/ - 11
y= 25
As we got y, we can put the value of y in equation 1 or equation 2.
3x+2y=395
3x+2*(25)=395
3x+50=395
3x=395-50
3x=345
x=345/3
x=115
As we assumed the book to x and pen to be y
price of book = Rs. 115
price of pen= Rs. 25