. (04.07) Luke is keeping track of the total number of hours he exercises. He started the summer having already put in 15 hours,
2 answers:
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Answer:
The number of bacteria after
days is given by
where is the initial number of bacteria.
Step-by-step explanation:
The number of bacteria in the sample triples every 10 days, this means after the first 10th day, the number of bacteria is
where is the initial number of bacteria in the sample.
After the 2nd 10th days, the number of bacteria is
after the 3rd day,
and so on.
Thus, the formula we get for the number of bacteria after the <em>n</em>th 10-days is
where is is the <em>n</em>th 10-days.
Since, is 10 days, we have
or
Substituting that into , we get:
Answer:
Step-by-step explanation:
Hello!
To test if boys are better in math classes than girls two random samples were taken:
Sample 1
X₁: score of a boy in calculus
n₁= 15
X[bar]₁= 82.3%
S₁= 5.6%
Sample 2
X₂: Score in the calculus of a girl
n₂= 12
X[bar]₂= 81.2%
S₂= 6.7%
To estimate per CI the difference between the mean percentage that boys obtained in calculus and the mean percentage that girls obtained in calculus, you need that both variables of interest come from normal populations.
To be able to use a pooled variance t-test you have to also assume that the population variances, although unknown, are equal.
Then you can calculate the interval as:
[(X[bar]_1-X[bar_2) ± *
]
[(82.3-81.2) ± 1.708* (6.11*]
[-2.94; 5.14]
Using a 90% confidence level you'd expect the interval [-2.94; 5.14] to contain the true value of the difference between the average percentage obtained in calculus by boys and the average percentage obtained in calculus by girls.
I hope this helps!