Stats and Probability

• t tables is used in 


  less than 30
• The mean, median and mode are all measures of central tendency
• Mean = sum of values / number of values
• Median = middle value when data is arranged in ascending or descending order
• Range = difference between highest and lowest value
• Mode = most frequently occurring value
• Mode = most frequent value
• Outliers are values that lie outside the interquartile range
• When is a Type I error committed?


  We reject a null hypothesis that is true.
• Which of the following is a Type I error

  𝐻o is true; reject 𝐻o.
• Which of the following describes an alternative hypothesis in a left-tailed test?


  𝐻�� <100
• It is also the probability of committing an incorrect decision about the null hypothesis.


  Level of significance
• In a one-tailed test, in which critical value listed below will the computed Z of 2.313 fall in the acceptance region?

  2.365
• It is a proposed explanation, assertion, or assumption about a population parameter or about the distribution of a random variable.

  Hypothesis
• Which of the following describes an alternative hypothesis using two-tailed test


  𝐻𝑎 ≠100
• When is a Type II error committed?


  We fail to reject a null hypothesis that is false.
• What is the statistical method used in making decisions using experimental data?


  Hypothesis Testing
• The introduction of modern computers affects the performance of the students.” What kind of hypothesis is it?


  null
• The average height of a 1-year old child is 29 inches. What is the parameter?


  the average height of 29 inches
• Which of the following population parameters is used as symbol for the mean or average population?


  ��
• Which of the following statements best describes a parameter?


  It describes the population.
• A researcher estimates that the average height of buildings in a large city is at least 700 feet. Based on the given data, which is the parameter?


  the average height of the building
• In formulating the alternative hypothesis, what mathematical symbol is applicable to use in the statement, “The average score of Grade 11 (ABM) in Business Statistics is 75?


  ≠
• In a commercial, a new diet program would like to claim that their methods result in a mean weight loss of more than 22kgs in two (2) weeks. To determine if this is a valid claim, they hire an agency that then selects 25 people to be placed on this diet. What is the test of hypothesis


  alternative
• A vacuum cleaner consumes less than 46 kwh per year. What hypothesis test can you use in this claim?

  left-tailed
• Which is the correct null hypothesis of the claim below? “Students take an average of less than five (5) years to graduate from college.”

  𝐻𝑜: µ = 5
• A parameter is...


  a numerical value that summarizes all the data of an entire population
• it is the area in the normal curve that leads to rejection of null hypothesis.

  rejection region
• Agree or Disagree?Z-test is applicable if the population standard deviation is known, and the number of samples is greater than 30?


  agree
• What statistical test is applicable if the population standard is unknown, and the number of samples is less than 30?

  T-test
• TRUE/FALSE. It is TWO-TAILED test if the alternative hypothesis is bidirectional

  true
• Z-test


  A statistical hypothesis test used when the population standard deviation is known and the sample size is large (usually greater than 30)
• Null hypothesis


  A statement that assumes there is no significant difference between the sample and population means
• Alternative hypothesis


  A statement that assumes there is a significant difference between the sample and population means
• Critical value


  A value determined by the chosen level of significance and the direction of the test, used to compare with the test statistic to make a decision
• Level of significance


  The probability of rejecting the null hypothesis when it is actually true, denoted by α
• One-tailed test


  A test in which the critical value is located on only one side of the sampling distribution
• Two-tailed test


  A test in which the critical value is located on both sides of the sampling distribution
• Population standard deviation


  The population standard deviation is the standard deviation of the entire population, denoted by σ
• Sample mean


  The sample mean is the average of the sample data, denoted by X