25 scores from all of the students who took the test. She sees that the mean score is 134 with a standard deviation of 6.0547. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 13. Is there evidence that the standard deviation of test scores has decreas

WE fail to reject the Null and conclude that ; Standard deviation of test hasn't decreased.

Step-by-step explanation:

The hypothesis :

H0 : σ = 13

H1 : σ < 13

Using the Chisquare Square statistic :

χ² = (n-1)*s²/σ²

Sample size, n = 25

s² = 6.0547²

σ² = 13²

χ² = (25 - 1)*6.0547² / 13²

χ² = 879.82541016 / 169

χ² = 5.206

The degree of freedom, df = 25 - 1 = 24

The Pvalue(5.206, 24) = 0.99981

Reject H0, if Pvalue < α ;

Since Pvalue > α ; WE fail to reject the Null and conclude that ; Standard deviation of test hasn't decreased.

geometric series converge the common ratio r has magnitude less than one.

which is equivalent to

for the example we need

|2-x| < 1

-1 < 2-x   and 2-x < 1

x < 3 and x > 1

we can write that

answer: 1 < x < 3

1a. common ratio r=250/25=10 > 1     diverges

1b.   r=50/100=1/2 converges

when these converge they converge to

where a is the first term.

answer: 200

1c. r=-1   so it's not the case that |r| < 1.     diverges

2a. x is the common ratio so we converge when |x|< 1

2b.   r=-10x / -2 = 5x.

we converge when

|5x| < 1

|x| < 1/5

2c.   r=3-2x

-1 < 3-2x and 3-2x < 1

-4 < -2x and 2 < 2x

x < 2 and 1 < x

1 < x < 2

2d. [/tex] r=-48x^3/12 = 4x^3[/tex]

|4x^3| < 1

|x^3| < \frac 1 4

|x| < 4^{-1/3}