because 1/2 is equal to 50%
0.5≠50
Answer:
C.
Step-by-step explanation:
Step-by-step explanation:
Given - In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen concrete has a low value of thermal conductivity in order to minimize subsequent damage due to changing temperatures. Suppose two types of concrete, a graded aggregate and a no-fines aggregate, are being considered for a certain road. The table below summarizes data on thermal conductivity from an experiment carried out to compare the two types of concrete.
Type ni xi si
Graded 42 0.486 0.187
No-fines 42 0.359 0.158
To find - a. Formulate the above in terms of a hypothesis testing problem.
b. Give the test statistic and its reference distribution (under the null hypothesis).
c. Report the p-value of the test statistic and use it to assess the evidence that this sample provides on the scientific question of difference in mean conductivity of the two materials at the 5% level of significance.
Proof -
a.)
Hypothesis testing problem :
H0 : There is significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.
H1 : There is no significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.
b)
Test statistic :




⇒Z(cal) = 3.3687
Z(tab) = 1.96
As Z (cal) > Z(tab)
So, we reject H0 at 5% Level of significance
p-value = 0.99962
Hence
There is significant difference in mean conductivity at the two materials.
Answer: 98 degrees
Step-by-step explanation:
Answer:
v = 15 miles / hour
Step-by-step explanation:
Given:
Distance covered by biker = s=45 miles
time taken by him = t=180 minutes
TO Find:
speed in miles per hour = v = ?
Solution:
As it is given that the distance covered is 45 miles
and time taken by him is 180 minutes
as one hour have 60 minutes
so time taken by rider = t = 180 /60
= 3 hours
this step is done because we have to find speed in miles per hour
Now
The formula for finding the distance is
distance = speed * time
or
s = v * t
we have to find v
so dividing both sides by t

it becomes

Putting the values

solving it gives
v = 15 miles / hour
which is the required speed
in the given options it is not available