Final answer:
The question appears to be related to child language development but interpreted in a statistical context; however, without specific data on 5-year-olds' use of conjunctions, we cannot provide a precise answer.
Step-by-step explanation:
The question "How many conjunctions do TD 5-year old use in a 15 minute sample?" seems to be related to a study of linguistics or child development rather than directly to mathematics. However, if we interpret this question in the context of statistics, which falls under the category of mathematics, we could be looking for an average or typical number of conjunctions used by 5-year-olds in a conversation sampled over 15 minutes. This data would need to be gathered from actual samples of children's speech and then analyzed. Unfortunately, the provided reference information does not specifically mention conjunctions used by 5-year-old children, therefore, we cannot give an accurate answer without the relevant study data.
Given the reference information, if you were investigating the provided statements regarding time such as 95 percent of samples with means under 26 minutes or the amount of time boys and girls play sports, you would be encountering statistical concepts used to analyze data. For example, the Central Limit Theorem helps in the understanding of how the distribution of sample means is a normal distribution, even when the population distribution is not normal, provided the sample size is large enough.