Answer: d. if we do not know the population standard deviation and must use the sample standard deviation.
Step-by-step explanation:
We use t-distribution is quite similar to distribution of z-score .
The interpretation of t-scores and z-scores are same.
T- distribution is used when the data is not accurately normal and when the population standard deviation is unknown.
In the absence of population standard deviation , we use the standard deviation of the sample.
So , We use a t distribution for inference about a population mean instead of the standard Normal distribution if we do not know the population standard deviation and must use the sample standard deviation.
Hence, the correct option is : d. if we do not know the population standard deviation and must use the sample standard deviation.
Average =
2 + 7 + 19 + 24 + 25
——————————
5
=
77
—
5
= 15.4
Answer:
3168 feet
Step-by-step explanation:
Do not know how to word explanation.
Since both have same speed
v(rel.) x-(-x)= 10( from law of vector addition)
2x=10,x= 5m/sec
Answer:
<u>25 minutes</u>
Step-by-step explanation:
From the table,
2 laps takes time 10 min.
4 laps takes time 20 min.
6 laps takes time 30 min.
8 laps takes time 40 min.
10 laps takes time 50 min.
So, we can deduce the relation between the number of laps and time
the time over the number of laps at each row = 5
Which mean 1 lap takes 5 minutes
Therefore, to run 5 laps, it takes = 5 * 5 = 25 minutes
