Question
23 Bcientiets conductad an investigation to detormine the relaborstip beveen age and fertility in men.
This investigation was dons from 1999 bo 2017 using 1294 heatty men from the age group
Men with cocupations (warking in environmerts) involing exposure to excessive heat were exctuded during the selection of particparite.
The procedure wes as follows:
- Semen was collected after 5 days of no senual activies.
- A specialised microsoope was used to deternine the spern count (number of normal sperm per ml of semen) and progressive motility (ability of sperm to swin eflectlvely in a straight ine).
- An electron microscope was used to determine sperm necrosis (immature/dead sperm per fresh semen sample).
2.3.1 Identify in this investigation the:
(a) Independent variable
(1)
(b) Dependent variable
(1)
2.32 State THREE ways in which the dependent variable was determined.
2.3.3 Glve TWO reasons why the investigation can be considered to be reliable.
2.3.4 Explain why men with occupations involving exposure to excessive heat were excluded from the investigation.
(3)
(2)
(3)
(10)
59
This investigation was dons from 1999 bo 2017 using 1294 heatty men from the age group
Men with cocupations (warking in environmerts) involing exposure to excessive heat were exctuded during the selection of particparite.
2.3.1 Identify in this investigation the:
(a) Independent variable
(1)
(b) Dependent variable
(1)
2.32 State THREE ways in which the dependent variable was determined.
2.3.3 Glve TWO reasons why the investigation can be considered to be reliable.
2.3.4 Explain why men with occupations involving exposure to excessive heat were excluded from the investigation.
(3)
(2)
(3)
(10)
59
Ask by Higgins Lawson. in South Africa
Mar 25,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
- Independent Variable: Age of the men.
- Dependent Variable: Fertility measured by sperm count, progressive motility, and sperm necrosis.
- Ways Dependent Variable Was Determined:
- Sperm count using a specialized microscope.
- Progressive motility using the same microscope.
- Sperm necrosis using an electron microscope.
- Reliability Reasons:
- Controlled for environmental factors by excluding men with heat-exposed occupations.
- Used standardized equipment to ensure accurate measurements.
- Exclusion of Heat-Exposed Men:
- To prevent heat from affecting sperm quality.
- To minimize confounding variables and ensure the study accurately reflects the relationship between age and fertility.
Solution
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Mind Expander
In this fascinating investigation, the independent variable is the age of the participants, as it’s the factor being altered to observe its impact on fertility. The dependent variable, on the other hand, is the fertility of the men, which is being measured in terms of sperm count, motility, and necrosis observed in the semen samples.
Determining the fertility involved three specific methods: first, they evaluated sperm count by counting the number of normal sperm in one milliliter of semen; second, they assessed progressive motility by observing the effectiveness and straightness of the sperm’s swimming patterns; and third, they utilized an electron microscope to establish the percentage of immature or dead sperm in the samples.
The reliability of the investigation can be discerned from its robust participant size of 1,294 healthy men, ensuring a diverse and representative sample. Additionally, the standardized procedures for collecting and analyzing seminal samples enhance consistency in the results, contributing to the credibility of the findings.
Men in heat-exposed occupations were excluded because such exposure can negatively impact sperm quality, leading to potentially skewed results. By controlling for this variable, the study aimed to isolate age as the primary factor influencing fertility, ensuring the investigation’s conclusions are more accurate and relevant.
