Expected Outcome
Calculate the expected value for playing this lottery game
X P(x)
$100 4/52
$20 4/52
$10 13/52
$0 31/52
11.73 - 15 = $-3.27
There is a 10% chance of snow on a given day in December. Find the probability that in a random sample of 25 days in December, it will snow exactly 2 days.
binompdf (n=25, p=.1, x=2)
There is a 10% chance of snow on a given day in December. Find the probability that the first day of snow is the 8th day you sample.
geompdf(p=.1, r=8)
What is the formula for mean of the binomial?
mu=np
Calculate the expected value for playing this lottery game
X P(x)
$100 12/52
$20 8/52
$10 30/52
$0 2/52
31.92 - 15 = $16.92
There is a 10% chance of snow on a given day in December. Find the probability that in a random sample of 25 days in December, it will snow less than 4 days.
binomcdf (n=25, p=.1, x = 3)
There is a 10% chance of snow on a given day in December. Find the probability that the first day of snow is within the first 11 you sample.
geomcdf(p=.1, p=11)
What is the probability that a teacher drinks 2 cups of coffee a day?
0 0.264
1 0.241
2 0.256
3 0.152
4 0.087
= 0.256
In the US, 21% of households use a clothesline to dry their laundry. Capucine would like to survey households that use a clothesline, so she plans to contact randomly selected US households until she finds one that uses one.
How many households would Capucine be expected to survey before finding the first one that uses a clothesline?
4.76
There is a 10% chance of snow on a given day in December. Find the probability that in a random sample of 25 days in December, it will snow more than 4 days.
1 - binomcdf(n=25, p=.1, x=4)
There is a 10% chance of snow on a given day in December. Find the probability that you sample more than 15 days before you the first day of snow.
1-geomcdf(p=.1, p=15)
What is the probability that a teacher drinks less than 3 cups of coffee a day?
0 0.264
1 0.241
2 0.256
3 0.152
4 0.087
=0.761
In the US, 21% of households use a clothesline to dry their laundry. Capucine would like to survey households that use a clothesline, so she plans to contact randomly selected US households until she finds one that uses one.
Compute the standard deviation.
4.232
There is a 10% chance of snow on a given day in December. Find the probability that in a random sample of 25 days in December, it will snow a minimum of 5 days
1 - binomcdf(n=25, p=.1, x = 4)
There is a 15% chance of someone having red hair. What is the mean number of people you would need to sample to find the first person with red hair?
1/.15 = 6.67
What is the mean?
0 0.264
1 0.241
2 0.256
3 0.152
4 0.087
mean = 1.557
Norfolk to Miami flights are on time 75% of the time. Suppose 200 flights are randomly selected.
How many flights can you expect to be on time?
150
There is a 10% chance of snow on a given day in December. Find the probability that in a random sample of 25 days in December, it will not snow more than 15 days.
1-binomcdf(n=25, p=.9, z =15)
OR
binomcdf (n=25, p=.1, x= 10)
There is a 10% chance of snow on a given day in December. Find the probability that the first day of snow either the 7th or 9th day you sample.
geompdf(p=.1, r=7)+geompdf(p=.1, r=9)
What is the standard deviation?
0 0.264
1 0.241
2 0.256
3 0.152
4 0.087
sd = 1.265