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Answer:
Therefore, the number of female statistics student ages that must be obtained in order to estimate the mean age of all female statistics student is 3625 female statistics student
Step-by-step explanation:
Here, we have
Where:
n = Required sample size
σ = Standard deviation = 18.3
E = Margin of error = 1/2 year
= Critical score from the confidence level = 1.645
Therefore,
Therefore, the number of female statistics student ages that must be obtained in order to estimate the mean age of all female statistics student = 3625 female statistics student.
Speed of boat in still water is 13 miles per hour and speed of current is 4 miles per hour
<h3><u><em>Solution:</em></u></h3>Let s = the speed of the boat in still water in miles/hour
Let c = the speed of the current in miles/hour
<em><u>Formula to remember:</u></em>
If the speed of a boat in still water is s miles/hr and the speed of the current is c miles/hr, then:
Speed downstream = (s + c) miles per hour
Speed upstream = (s - c) miles per hour
<em><u>Given:</u></em>
boat traveled 153 miles downstream and back
distance for downstream = 153 miles
distance for upstream = 153 miles
time taken for downstream = 9 hours
Time taken for upstream = 17 hours
<em><u>The relation between speed, distance and time is given as:</u></em>
<em><u>For downstream:</u></em>
s + c = 17 ------- eqn 1
<em><u>For upstream:</u></em>
s - c = 9 ------- eqn 2
<em><u>Let us solve eqn 1 and eqn 2 to find values of "s" and "c"</u></em>
Add eqn 1 and eqn 2
s + c = 17
s - c = 9
(+) -------------
2s = 26
<h3>s = 13</h3>Substitute s = 13 in eqn 1
13 + c = 17
c = 17 - 13 = 4
<h3>c = 4</h3>Thus the speed of boat in still water is 13 miles per hour and speed of current is 4 miles per hour