Q1) Mean weight of loads of coal placed in train cars by loading machine is 43.0 tons with standard deviation of 8.0 tons. Suppose that weight of loads placed in train cars by this loader are normally distributed, if random sample of 9 loads is selected for weight check, determine probability that mean weight of those loads is more than 40.60 tons.
Company operates four machines in three shifts each day. From production records, data in table below were collected. At.05 level of significance test to find out if number of breakdowns is independent of shift.
|
|
Machine
|
|
Shift
|
A
|
B
|
C
|
D
|
|
1
|
41
|
20
|
12
|
16
|
|
2
|
31
|
11
|
9
|
14
|
|
3
|
15
|
17
|
16
|
10
|
a) Number of breakdowns is dependent on shift, as the test value 11.649 is less than critical value of 12.592.
b) Claim that number of breakdowns is independent of shift can't be rejected, as test value 11.649 is less than the critical value of 12.592.
c) Number of breakdowns is dependent on shift, as the p-value is .07.
d) Number of breakdowns is independent of shift, as test value 12.592 is greater than critical value of 11.649.