2m3 is. not over3 because. 2is lower than 3
Answer:
t distribution behaves like standard normal distribution as the number of freedom increases.
Step-by-step explanation:
The question is missing. I will give a general information on t distribution.
t-distribution is used instead of normal distribution when the <em>sample size is small (usually smaller than 30) </em>or <em>population standard deviation is unknown</em>.
Degrees of freedom is the number of values in a sample that are free to vary. As the number of degrees of freedom for a t-distribution increases, the distribution looks more like normal distribution and follows the same characteristics.
Answer:
A certain company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of a battery is normally distributed, with a mean of 50 months and a standard deviation of 9 months. If the company does not want to make refunds for more than 10% of its batteries under the full-refund guarantee policy, for how long should the company guarantee the batteries?
The company should guarantee the batteries for 38 months.
Step-by-step explanation:
Using standard normal table,
P(Z < z) = 10%
=(Z < z) = 0.10
= P(Z <- 1.28 ) = 0.10
z = -1.28
Using z-score formula
x = zσ + μ
x = -1.28 *9+50
x = 38
Therefore, the company should guarantee the batteries for 38 months.
Answer:
5y=2
Step-by-step explanation:
8y + 4 = 6 + 2y + 1y
Combine like terms
8y+4 = 6+3y
Subtract 3y from each side
8y-3y+4 = 6+3y-3y
5y +4 = 6
subtract 4 from each side
5y+4-4 = 6-2
5y=2
