In my opinion, the speaker heard the ghost.
Answer: the population has a mean of less than 30
Explanation:
In interval estimation, the t distribution is applicable only when a. the population has a mean of less than 30. the sample standard deviation (s) is given instead of the population standard deviation
The ability to generalize a study's results to different circumstances is known as external validity that suffers from 7 types of threats.
<h3>What are the threats to External Validity?</h3>
There are 7 major threats to external validity.
- The first threat is sampling bias, in which a sample is not representative of the population.
- The second threat is history, where an unrelated incident can affect the results.
- The third threat is observer bias, in which the traits or actions of the experimenter unintentionally affect the results, resulting in bias and other demand features.
- The fourth threat is the Hawthorne effect, which describes the propensity for individuals to alter their behaviour merely because they are aware that they are being observed.
- The fifth threat is the Testing Effect, in which the results are impacted by whether a test is administered before or after another.
- The sixth threat is the aptitude-treatment, which involves the interaction of individual and group factors to affect the dependent variable.
- The environment, time of day, location, researcher traits, and other variables that restrict the generalizability of the results are included in the seventh threat.
To learn more about external validity, refer:
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The projected population size in 2030 will be : ≈ 44159
First step : determine the population growth rate
Gr = change in population / time
= ( 1500 - 1100 ) / 1 year
= 400 = 36%
<h3>Determine the projected population size </h3>
applying Malthus's population projection.
Pp = P₁ ( 1 + r )ⁿ
where ; P₁ = 1500, r = 0.36 , n = ( 2030 - 2019 ) = 11 years
Pp = 1500 ( 1 + 0.36 )¹¹
= 1500 ( 29.439 )
= 44158.5 ≈ 44159
Hence we can conclude that the projected population size as at 2030 is 44159
Learn more about projected population : brainly.com/question/25896797
