Statistics

Question 1

What is a null hypothesis?

Answer 1

There is no significant difference between 2 sets of data

Question 2

What is the null hypothesis of the correlation coefficient?

Answer 2

There is no significant correlation …

Question 3

When would you use the chi-squared test?

Answer 3

Comparing observed and expected values

Question 4

What level of probability do scientists always use?

Answer 4

0.05

Question 5

What does a 0.05 probability show?

Answer 5

95% confidence difference is significant and 5% due to chance

Question 6

What are degrees of freedom?

Answer 6

The number of variables that are free to change

Question 7

How do you calculate the dof for chi-squared test?

Answer 7

(n)-1

Question 8

When do you reject the null hypothesis?

Answer 8

When your calculated value is higher than your critical value at 0.05 probability

Question 9

What are the statistical analysis steps?

Answer 9

Null hypothesis
Select appropriate test
Carry out calculation
Dof
Compare calculated value to critical value

Question 10

What is the chi-squared equation?

Answer 10

(observed-expected)^2
Sum of ——————————–
Expected value

Question 11

How do you get the observed value?

Answer 11

From the question

Question 12

How do you get the expected value?

Answer 12

Use ratio given

Question 13

What should your table look like for calculating chi-squared?

Answer 13

O E O-E (O-E)^2 (O-E)^2/E

Question 14

When would you use a t-test?

Answer 14

When looking for a significant difference between 2 sets of data

Question 15

What is the equation for SD?

Answer 15

√Σ( each score - mean)^2
———————————
number of values - 1

Question 16

What is the equation for t-test?

Answer 16

(x1 - x2)
-----------------------
√(s1)^2      (s2)^2
 ----------  +  ---------
   n1               n2

x1 = mean value of 1st sample
x2 = mean value of 2nd sample
s1 = SD 1st sample
s2 = SD 2nd sample
n1 = no. of measurements 1st sample
n2 = no. of measurements 2nd sample

Question 17

What is the first SD within and tell you?

Answer 17

68% of data is either +/- from mean

Question 18

When do you use the correlation coefficient test?

Answer 18

If there is a significant correlation between 2 variables

Question 19

What must the r value for correlation coefficient always be?

Answer 19

Between -1 and +1

Question 20

What is the R value if points increasing linear?

Answer 20

+1

Question 21

What is the R value if points decreasing linear?

Answer 21

-1

Question 22

What is the R value if points are scattered and random?

Answer 22

0.0

Question 23

What is equation for correlation coefficient?

Answer 23

LOOK IN BOOK + LEARN

Question 24

What should the table look like for correlation coefficient?

Answer 24

X Y X^2 Y^2 XY

TOTAL