The image is kinda blurry, but from what I can gather, the notation in the attachment means
![p_X[x_k]\equiv\mathbb P(X=k)=\begin{cases}(1-p)^{k-1}p&\text{for }k=1,2,\ldots\\0&\text{otherwise}\end{cases}](https://tex.z-dn.net/?f=p_X%5Bx_k%5D%5Cequiv%5Cmathbb%20P%28X%3Dk%29%3D%5Cbegin%7Bcases%7D%281-p%29%5E%7Bk-1%7Dp%26%5Ctext%7Bfor%20%7Dk%3D1%2C2%2C%5Cldots%5C%5C0%26%5Ctext%7Botherwise%7D%5Cend%7Bcases%7D)
Then
a)
![p_X[x_k\le4]\equiv\mathbb P(X\le4)=\mathbb P(X=1)+\mathbb P(X=2)+\mathbb P(X=3)+\mathbb P(X=4)](https://tex.z-dn.net/?f=p_X%5Bx_k%5Cle4%5D%5Cequiv%5Cmathbb%20P%28X%5Cle4%29%3D%5Cmathbb%20P%28X%3D1%29%2B%5Cmathbb%20P%28X%3D2%29%2B%5Cmathbb%20P%28X%3D3%29%2B%5Cmathbb%20P%28X%3D4%29)
b)

c)
7 girls participated only in Karate.
21 + 8 = 29
29 + 7 = 36
36 + 6 = 43
Answer:
The standard error of the sample mean is 0.57
Step-by-step explanation:
we know that
The Standard Error Formula is given by the formula

where:
SE = standard error
s = standard deviation
n = the sample size
In this problem we have

substitute in the formula


Answer:
EF=6
Step-by-step explanation:
E is the midpoint, so DE = EF
DE = 15-3x
EF = x+ 3
Since DE = EF,
15 - 3x = x + 3
-4x = -12
x = 3
If x = 3,
DE = 15 - 3*3, 15 - 9 = 6
EF = x+ 3, so EF = 3 + 3 = 6
Every whole number is a rational number because its a whole number meaning it's not a fraction becasue fractions are irrational numbers.
~ All whole numbers are rational but not all rational numbers are whole.
Hope this helps!!! :D