Answer:
Maridel wants to find out how many of her classmates plan to come to the next football game. There are 800 students in her school. She selects a sample of the population by putting the names of every student into a bag and drawing out 100 names.
Which statement(s) describe her sampling method? Check all that apply.
A) Her method will produce a biased sample.
<u>B) Her method will produce a valid sample.</u>
<u>C) Her method will produce a random sample.</u>
<u>D) Her method will produce a representative sample.</u>
E) Her method will produce an invalid sample.
Step-by-step explanation:
Let x be rate of boat in still water
let y be rate of current
we use this equation to relate quantities:
distance = speed · time
we have two unknowns so we might need to create a system of equationss
upstream:
speed (in km/h) = x - y
(we get speed of boat then subtract the current's speed from it since current is going against boat direction)
time = 3 hours
distance = 144 km
downstream:
speed (in hm/h) = x + y
(we get speed of boat then add the current's spd from it since current is going against boat direction)
time = 2 hours
distance = 144 km (same distance upstream and downstream)
using distance = speed times time
for upstream
144 = 3(x-y)
144 = 3x - 3y
for downstream
144 = 2(x+y)
72 = x + y
system of eqns:
144 = 3x - 3y
72 = x + y
solve by substitution: move 72 = x + y into x = 72 - y and subst into other equation for x
144 = 3(72 - y) - 3y
144 = 216 - 3y - 3y
144 = 216 - 6y
144 - 216 = -6y
-72 = -6y
y = 12 km/h
Use x = 72 - y to find x with y = 12: x = 72 - 12 = 60 km/h
rate of boat in still water is 60 km/h
rate of the current is 12 km/h
Answer:
9 teams
Step-by-step explanation:
If the total games played was 36 and no team played each other twice, we need to ensure there isn't any double counting.
36 = (n-1) + (n-2) + (n-3) ... + (n-(n-1))
using this knowledge, we can then count up:
1+2+3+4+5+6+7+8 = 36
If our highest number is 8, then we know there must be 9 teams, because no team can play themselves.
Answer:
P(-2,7)
P'(-2,-7), ANSWER
reflection across the x-axis rule:
(×,y) ===> (x,-y)
Easy way to do this is draw the point on graph paper and count the same units above/below the x-axis. This example you are 7 units above the x-axis so you would count 7 units below the x-axis giving you the point.
Answer:
<h2>The answer is 0.23(approx).</h2>
Step-by-step explanation:
The given die is a three sided die, hence, there are only three possibilities of getting the outcomes.
We need to find the probability of getting exactly 3s as the result.
From the sequence of 6 independent rolls, 2 rolls can be chosen in 
ways.
The probability of getting two 3 as outcome is 
.
In the rest of the 4 sequences, will not be any 3 as outcome.
Probability of not getting a outcome rather than 3 is 
.
Hence, the required probability is 
≅0.2966 or, 0.23.
