Answer:
b. 2.01 < σ < 2.81
Step-by-step explanation:
The 90% confidence interval for the population standard deviation is calculated as:
< σ < 
Where n is equal to 51, s is equal to 2.34,
is 10%,
is the value for the Chi squared distribution with n-1 degrees of freedom that has a probability of
in the right tail and
is the value for the Chi squared distribution with n-1 degrees of freedom that has a probability of
in the right tail.
So, replacing n by 51, s by 2.34,
by 67.50 and
by 34.76, we get that the The 90% confidence interval is equal to:
< σ <
2.01 < σ < 2.81
Answer:
-12°C
Step-by-step explanation:
6AM = 2°C
8AM= -2°C
10AM= -6°C
12AM= -8°C
2PM= -12°C
ANSWER

and
e have
EXPLANATION


Let us make y the subject and call it equation (2)


We put equation (2) in to equation (1)



Simplify to get,


Divide both sides by 31,



We put this value in to equation (2) to get,


We collect LCM to obtain,

