Flashcards
Statistics - Data and Probability 1
Cards in this deck (25)
- 1Numerical measures Upper quartile Lower quartileUpper quartile: 3/4(n+1)
Lower quartile: 1/4(n+1) - 2Formula for SOnly use one of the two equations. Depending on what information is given in the question.
- 3Standard Deviation and VarianceStandard Deciation
=
√Variance
(σ = √ σ ²)
——————————
Variance
=
Standard Deviation ²
(σ=σ ²) - 4Mean Standard Deviation VarianceMean(aX+b) = aMean(X)+b
SD(aX+b) = aSD(X)
Var(aX+b) = a²Var(X) - 5Probability Relative frequencyRelative frequency(A) = number of times event A occurs
———————————
Total number of trials
P(A) = n(A)
——
N - 6A’ A u B A n B A n (B u C) P(A u B) P(A u B)A’ = Does not include A
A u B = A or B or both
A n B = A and B
A n (B u C) = A and is B or C
P(A u B) = P(A) + P(B)
P(A u B) = P(A) + P(B) - P(A n B) - 7Different was of working out P(A n B)P(A n B) = P(A) x P(B)
P(A n B) = P(A) x P(B|A)
P(B n A) = P(B) x P(A|B) - 8Binomial Distribution What does X ~ B(n,p) mean?X ~ B(n,p)
n = number of trials
p = Probability if the event occurring - 9Work out the: Mean Variance Standard DeviationMean = μ = np
Variance = σ² = np(1-p)
Standard deviation = σ = √np(1-p) - 10Normal Distribution What does X~N(μ-σ²) mean?X~N(μ-σ²)
μ= mean
σ²= variance - 11Formula to work out ZZ=X~N(0,1²)
OR
Z= X-μ
——
σ - 12Regression What equation is useda = where the line crosses the y axis
b = the gradient of the line
- 13Explain the equationWhen X increases by 1 unit. Y increases by B.
Then evaluate in context - 14What do the values of r show?r <0 = below the regression line
r >0 = above the regression line
r =0 = on the regression line - 15Correlation What is the equation to find r?Or on calculator:
Menu 2, calc, reg, X, a+bX
- 16What does the value of r mean?0.9 ≤ r < 1 = very strong
0.7 ≤ r < 0.9 = strong
0.3 ≤ r < 0.7 = moderate
r < 0.3 = weak
To find rs (Spearman’s regression/correlation then rank numbers first and use r) - 17Normal approximation to binomialIf X~B(n,p) then X≈N(np,np(1-p)
BUT ONLY IF:
n is large (n≥20) and p≈0.5
OR
np≥10 and np(1-p)≥10 - 18Discrete probability distributionsP(X=x)
Mean= μ = Σ(X) = ΣxP(X=x)
Var(X) = σ² = Σ(x-μ)²
Var(X) = σ² = Σ(X²)-μ²
- 19How does it affect the mean and varianceE(a)=a
E(aX)=aE(X)
E(aX+b)=aE(X)+b
Var(a)=0
Var(aX)=a²Var(X)
Var(aX+b)=a²Var(X) - 20Sampling Random SamplingLabel each population from 001 to n. Use a random number generator to get random numbers with ... digits. Ignore 000 and anything >n. Ignore repeats. After selecting the specified amount select the corresponding population of the sample.
- 21Cluster samplingDivide the population into the given groups. Then a random sample of n is picked from a cluster. Or a few clusters proportionally.
- 22Systematic samplingOrder the sample from 000 to ... Pick a random number from 000 to ... and then pick every 10th/2nd/20th etc. Population until you have the specified amount and pick the corresponding population
- 23Stratified samplingFIND THIS OUT
- 24Estimationx̄~N(μ, σ²)
—
√n - 25How to work out ZZ = X̄ - μ
———
σ
——
√n
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- A level Statistics Flashcards on Statistics - Data and Probability 1, created by Tas Yale on 04/07/2018.
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- Tas Yale
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