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Flashcards 2021-11-25 How would you write the probability that $B$ occurs, given that $A$ has already occurred?? $$ P(B|A) $$ What is true about $P(A|B)$ for independent events?? $$ P(A|B) = P(A|B') = P(A) $$ How would you calculate $P(A | B)$?? $$ \frac{0.15}{0.15 + 0.25} $$ How would you calculate $P(A | A \cup B)$?? $$ \frac{0.15}{0.4 + 0.15 + 0.25} $$ How would you calculate $P(A' | B')$?? $$ \frac{0.2}{1-0.15-0.25} $$ Why do you have to be careful dealing with conditional probabilities involving things like “given $B'$”?

See Also [[Stats - Binomial Distribution]]S Flashcards What is the notation for $X$ being a random variable following a normal distribution with mode $\mu$ and standard deviation $\sigma$?? $$ X ~ N(\mu, \sigma^2) $$ What is this?? The normal distribution. What is the area under the normal distribution?? $$ 1 $$ What is required for a random variable $X$ to follow a normal distribution?? It has to be continious. How would you find $P(170 < X < 190)$ for the normal distribution?

See Also Flashcards What is hypothesis testing?? Determining how likely observed data occured by chance. What is the notation for the null hypothesis?? $$ H_0 $$ What is the notation for the alternate hypothesis?? $$ H_1 $$ What is a population parameter?? A statistic that summarises some information about a population. In the A-level, what’s the definition of a hypothesis?? Some statement made about a population parameter. In a binomial distribution, what is the population parameter?

See Also [[Stats - Statistical Distributions]]S [[Stats - Probability]]S [[Maths - Combinations]]?? Flashcards What $ \left(\begin{matrix} n \ r \end{matrix}\right) $ could you write for the number of ways you can pick $3$ students from a class of $28$?? $$ \left(\begin{matrix} 28 \\ 3 \end{matrix}\right) $$ What $ \left(\begin{matrix} n \ r \end{matrix}\right) $ could you write for the number of ways you could pick $2$ left-handed people from a total of $3$ people?

See Also [[Stats - Binomial Distribution]]S [[Stats - Probability]]S Flashcards What is a random variable?? A variable whose value depends on the outcome of a random event. What is the notation for a random variable?? Capital letters, $X$. What is the notation for the random variable $X$ taking a particular value $x$?? $$ P(X = x) $$ Can you explain $P(X = x) The probability that the outcome of the random variable $X$ was the specific outcome $x$.

What two forms do you give answers to probability questions?? Decimals Fractions What does $P(\text{experiment})$ mean?? The probability of experiment. In terms of probability, what is an experiment?? A repeatable process that gives rise to a number of outcomes. In terms of probability, what is an event?? A set of one or more outcomes. What is sample space?? The set of all possible outcomes. 2021-01-21 What does it mean for two events to be mutually exclusive?

Flashcards 2020-12-10 What do you call data with two variables?? Bivariate data. What is bivariate data?? Data with two variables. What is correlation?? A measure of the strength and type of a relationship between two variables. What type of correlation is this?? Strong positive correlation. What type of correlation is this?? Weak positive correlation. What type of correlation is this?? Strong negative correlation. What type of correlation is this?? Weak negative correlation. What type of correlation is this?

What sort of data do you normally use bar charts with?? Discrete data. What sort of data do you normally use histograms with?? Continous data. At GCSE, what was the frequency in a histogram?? The area of a column. Why is the GCSE definition of a histogram incorrect at A-level?? The area of the bars is not always frequency; it can be scaled by a scaling factor. If the frequency reads $30$ from a table, but is $60$ on a histogram, what is the scaling factor?

See also: [[Stats - Median, Quartiles and Percentiles]]S What goes on the $x$-axis on a cumulative frequency diagram?? The variable being measured. What does on the $y$-axis on a cumulative frequency diagram?? Cumulative frequency. What is the purpose of a cumulative frequency diagram?? It allows you to find estimates for medians, quartiles and percentiles. Drawing a cumulative frequency diagram is like what other process in stats?? Linear interpolation. When plotting a cumulative frequency diagram for grouped data, which class boundary should you use for the point on the $x$-axis?

What is an outlier?? An extreme value. What is an outlier which is not correct called?? An anomaly. What is the process of removing anomalies called?? Cleaning the data. What does $\ll$ mean?? Much less than. What does $\gg$ mean?? Much greater than. What is the typical definition of an outlier?? Any value that is over $1.5$ the interquartile range away from the upper or lower quartile. Should you add an outlier to a box plot?

How would a mean height change if everyone stood on chairs?? It would increase by the height of the chairs. How would a standard deviation for height change if everyone stood on chairs?? It would not change. How would a mean height change if everyone was 3 times taller?? It would be 3 times bigger. How would a standard deviation for height change if everyone was 3 times taller?? It would be 3 times bigger.

What data does Pearson’s large data set contain?? Information from weather stations. When did the weather stations in Pearson’s large data set record data?? May-Oct 1987 May-Oct 2015 Why was Oct 1987 of interest?? Because of The Great Storm. What are the units for mean temperature?? ^{\circ} C What are the units for total rainfall?? $mm$ What does tr/trace mean in relation to total rainfall?? Less than 0.05mm rain. What are the units for total sunshine?